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Trust in the Sharing Economy: the AirBnB case


Purpose
The purpose of this paper is to examine sharing economy online marketplaces with the aim of understanding how trust perceptions form and get communicated through sharing economy platforms.


Design/methodology/approach
The authors build on online user comments and reviews as aggregated by independent third-party websites, and apply a qualitative analysis.


Findings
The findings show that the quantity of information and communication are important drivers towards building trust perceptions, while an overall lack of interaction between users and the marketplace provider intensifies perceived risks.


Originality/value
The authors validated the importance of trust and the authors have illustrated that the critical conditions that hinder trust formation are information asymmetry as well as the lack of interaction. What is also an interesting implication is that the impact of both of these can be exacerbated when there is a perceived lack of support among users and between them and the marketplace operator.



Trust in the Sharing Economy: the AirBnB case 1. Introduction
The global economy is witnessing the emergence of the 'sharing economy', a form of electronic marketplaces where under-utilised resources and assets, are re-utilised or re-combined to create value. Platforms such as AirBnB and Uber have changed the way people travel and find a place to live. What these business models have in common is the collaborative basis operations, where peers transact with unknown others. For example, in the case of AirBnB, individuals rent out part, or their entire home for short stays. In this example, engaging with the platform entails an individual placing their trust in unknown and therefore untrusted others. Furthermore, the unknown others are private individuals, rather than familiar service providers who could be potentially perceived as trustworthy due to their reputations (Lai and Tong, 2013).
Trust perceptions are critical for the success of such platforms, and their highly dynamic, self-regulating, and fragile nature necessitates fresh examination of such issues. The greatest difference between sharing economy platforms and more conventional ones is that transactions are initiated online but concluded with an element of physical interaction when the online parties meet offline and face to face. This suggests that within this context there is a risk for a seller in terms of, for instance, the sharing of personal assets, or their personal residence location being identified, which is less intense in other contexts, and less researched by the existing literature (ter Huurne et al., 2017).
This study consider the issues of perceived trust emerging from the use of sharing economy marketplaces, with a particular focus on how these are communicated through the available online review systems. Due to the emergent and salient features of the online ecosystems, research into such e-marketplaces face new challenges. For example, the peer review system on the backbone of a distributed network of peers of any background and from anywhere is unprecedented in any business sector. Text feedback is becoming ever more popular and contains rich qualitative information about perception, preferences and behaviour with research showing that online reviews exert significant influence on other users' buying choices (Matzat and Snijders, 2012).
Our aim is to understand how trust perceptions form within the context of the online review system of a sharing economy marketplace. This allows us to understand the factors around which existing users tend to focus their reviews, as well as identify how these get communicated to prospective users. To achieve this aim, we formed the research question: "What are the factors that drive trust perceptions and are communicated through the online review system of a sharing economy marketplace"? To address this, we draw on user reviews published in AirBnB's own online platform and an independent review site that publishes user feedback for different online and offline businesses. In this paper, we consider both the technology used, as well as the wider context within which the outcomes of communication take place, and present an interpretive case study in order to offer a rich description of how trust and risk emerge within these marketplaces (Orlikowski and Baroudi, 1991).
The paper is structured as follows. First, the existing literature is reviewed to discuss core concepts pertaining to trust.
Then we present our approach for analysing our case study that leads to offering details concerning our methods. This is followed by a discussion of our findings and our concluding remarks.

Antecedents of Trust
Trust typically denotes a person's beliefs that others will behave as expected, socially appropriately and that they will fulfil their obligations (Fan et al., 2018). In addition, trust can be seen as one's willingness to be vulnerable to another's actions based on expectations and previous behaviour (Cheng et al., 2019). In our study, we consider trust as a guest's belief that the other party (specifically the AirBnB host), will behave appropriately and in a benevolent manner, with the aim to provide them with a good guest experience, based on the experiences of other guests with the same host.
Within online environments, and when compared to face-to-face environments, it is more difficult to gain one's trust and further maintain it (Chen and Cheung, 2019). Within an e-commerce environment specifically, Ratnasingam (2005) argues that trust has two different forms: trust in the technology and trust in the partner. The former relates to assurances, certifications and beliefs that the technological infrastructure and the policies can minimise the risks, whereas the latter relates to one's dispositional trust, and an evaluation of one's competence, among other things (Mayer et al., 1995). As far as the antecedents of trust are concerned, McKnight et al. (1998) suggest that these are the institutional mechanisms (institution-based trust), dispositional trust (personality-based trust), familiarity and one's first impression of the other party (knowledgeand cognition-based trust), and a cost-benefits analysis (calculative-based trust).
Considering these one by one, institution-based trust may take the form of clear and binding rules and regulations (e.g., escrow) pertaining to the mode of transaction (Pavlou and Gefen, 2004). Indeed, when rules and regulations are in place, users are more confident that the other party will behave as expected, and experience a greater level of trust, assuming risks away (Gefen, 2002). Cognition-based trust is often addressed through the concepts of privacy and security protection, and information quality (Kim et al., 2008). Privacy and security protection pertain to user's perceptions that the necessary security measures exist and that sensitive information will remain protected.
Information quality, on the other hand, relates to the accuracy and the completeness of the available information, but also to the ease of locating and using it (Miranda and Saunders, 2003). Next, knowledge-based trust is seen as the combination of one's perceived competence, benevolence and integrity (Lin, 2011), and highlights the importance of shared goals and understanding (Chen et al., 2014). Further, knowledge-based trust feeds into expectations where the more information is offered the easier it is to predict behaviour with a likelihood outcome of trusting the other party (Matzat and Snijders, 2012). Lastly, calculative-based trust can be seen as a cost-benefit analysis whereby users assess the costs in relation to the benefits emanating from their collaboration (Gefen et al., 2003). Generally, it has been shown that the perceived risk tends to decrease as perceived benefits increase and vice versa .
Within this context, trust suggests balancing the rewards from maintaining a relationship with the other party to the costs from resolving it (Zhao et al., 2017).

Trust in the Sharing Economy
Trust is pivotal to the normal conduct and survival of any online business (Subba Rao et al., 2007) and is of the utmost importance for users' continuance intentions towards a particular online service (Zhou et al., 2018). For sharing economy platforms, it is even more crucial (Cheng et al., 2019). Despite the value of institution-based mechanisms, particularly when transacting with someone for the very first time, the concept is also tied to social dimensions and structures, that can only produce trust when they refer to well established and stable over time institutions (Lane and Bachmann, 1996). This is not the case for sharing economy marketplaces (Laurell and Sandström, 2017), where participating parties may not be particularly familiar with the marketplace's underlying structures and operations.
Similarly, existing users may have expectations that relate more to previous experiences in similar yet different environments, such as regular e-commerce and hospitality contexts, where the brand name and the reputation of a seller can facilitate trust (ter Huurne et al., 2017). Therefore, we expect that risk will relate not only to one's past experience with the same technology or service, but also to the accumulated experience of using alternatives and similar platforms and marketplaces.
In the sharing economy, users will eventually have face-to-face interactions when making use of the underutilised resources, which can be experienced as infringement of one's privacy (Teubner and Flath, 2019). Therefore, some assurances are necessary to meet privacy and safety expectations. This is essential since trustworthiness, fair treatment, and keeping promises can lead to continuous use of the service (Pavlou and Dimoka, 2006). Information quality and availability can contribute significantly toward strengthening cognition-based trust (Otterbacher, 2011), as the relevant provision would counteract the information asymmetry that typically exists in such contexts (Yoganarasimhan, 2013). This is also relevant for facilitating knowledge-based trust perceptions, where users, most often, transact with other parties who are individual users (versus established businesses) and therefore, it is difficult to straightforwardly evaluate the reputation of another user and be confident they will behave in good faith. However, opportunistic behaviour is always possible, and the sharing economy has increased the scope for uncertainty, where peer to peer letting does not involve change of ownership.
Having said that, perceived risk is related to perceived benefits (Gefen et al., 2003). As products and services do not get exchanged in a permanent fashion, 'sharing' is not without financial gain for those involved. Instead, it is expected that all will gain something and that individual users can access more easily and for lower costs assets that they could not otherwise own or use through more traditional routes. Therefore, from a cost-benefit analysis, participants will need to weigh the perceived benefits and judge whether these outweigh the possible costs of participating (Pfeffer-Gillett, 2016).

The Impact of Online Reviews
Existing literature highlights the importance of feedback, such as online reviews and reputation systems (Noorian and Ulieru, 2010). These approaches can be used for appreciating one's intentions (Pavlou and Dimoka, 2006) and online reviews are treated as "a major form of computer-mediated communication" (Singh et al., 2016(Singh et al., , p. 1112 with an important impact (Torres et al., 2015). For the hospitality sector, Siering et al. (2018) argue that such user generated content is actively used by prospective travellers as an information source for lodgings and destinations and for making their decisions.
Today, there is increased competition among hospitality businesses to achieve the highest possible ratings from their guests (Gössling et al., 2018). As travellers have access to rich information (both in quantity and quality terms), they are able to assess the offerings of accommodations (Casaló et al., 2015). For two-sided review systems in particular, where both guests and host can leave reviews for each other, as in the case of AirBnB, it has been found that reviews are generally more positive (Bridges and Vásquez, 2016), but that negative reviews are often perceived as more credible and authentic (Zhang, 2019). In all cases however, online reviews in such platforms are critical because they help build trust (Bulchand-Gidumal and Melián-González, 2019).
As this study is focused around the concept of trust and how such perceptions are communicated through review systems, it is important to note that online reviews are used by users not only for making a decision, but also as a way to get insight into somebody else's prior experience (Torres et al., 2015). In other words, online reviews can be used as an information source into prior consumer experiences and for disentangling the different service features that impact on user perceptions (Siering et al., 2018). Moreover, online reviews tend to be seen as more useful compared to more standardised information (such as security assurances and certifications), especially because they communicate the actual experiences of others (Cheng et al., 2019).
While previous studies on trust have thoroughly examined different types on online marketplaces, particularly with respect to the sharing economy research on trust is comparatively scarce (ter Huurne et al., 2017). In this study we posit that the availability of textual information via online reviews provides numerous opportunities for both guests and hosts. Guests can use them to proceed with an informed decision making regarding their choices. Hosts can use the feedback towards understanding which services are valued most and identify specific ways towards supporting particularly their guests' trust perceptions. In doing so, we pay attention to the fact that communication between participants happens both online and offline and we therefore focus on how trust perceptions get communicated via an online review system, acknowledging that users leave feedback aiming precisely to convey their own experiences to others, while communicating both facts and opinions (Otterbacher, 2011).

Case Study Description: AirBnB
AirBnB is a community-oriented online marketplace that enables individuals to share, for a profit, their spare space, such as rooms or flats. As this study is focused on trust perceptions communicated through the online reviews, our description of the case is primarily devoted to aspects of the user interface, the communication tools and the review system.
The most important feature for enhancing trust is Airbnb's review system. The review system allows quests and host to provide reviews and ratings on a five-star scale. The review system underwent several modifications over the last years. In 2014, to reduce the risk of reprisal, Airbnb introduced a 14-day period during which host and guest can write a review that is only published either after both parties have completed their review or at the end of that period. The aim of this policy is to reduce the fear of retaliation in the case of bad reviews. Airbnb also introduced a separate facility to leave private feedback, enabling members to express their dissatisfaction without their feedback being made public. In August 2017, following an intervention of the Competition and Market Authority (UK), a further modification to the review system was introduced by allowing guests who either cancel their stay or leave early, because the property does not meet their expectations, to write a review.
AirBnB participation is subject to rules and regulations set forth by AirBnB's Terms of Service. Guests can search for a lodging and rent it following the host's approval. This suggests that the host can decline any booking with no penalties. If the host does accept the request and confirms the booking, the host can still cancel the booking at a future stage; in this case, both the guest and host are subjected to penalties with the service fees of the intermediary being non-refundable and a financial penalty for the host. Prospective guests are also able to cancel a booking. Similarly, the service fee is not refunded, and the booking fees may be refunded, but at the host's discretion. Regarding payments, AirBnB requires users to make advance payments of the entire amount (including the firm's commission), which are withheld until the period of the booking, even if the booking is for a year ahead. Finally, AirBnB accepts no liability for the use of its platform, and explicitly informs users that this should adhere to local regulations and legislation (e.g., zoning, taxation).

Method
This study is focused on trust perceptions within the context of the sharing economy, and we use the AirBnB marketplace as our case study. Our aim is to understand how trust perceptions form within the context of the online review system of a sharing economy marketplace and how these perceptions are communicated among participants through the online review system of such platforms. The specific research question that we address is "What are the factors that drive trust perceptions and are communicated through the online review system of a sharing economy marketplace"? and our objective is to identify the features of online and offline interactions between hosts and guests that are communicated to prospective users with the aim to help them build trust perceptions.
In this study, we chose the design of a single case study around the AirBnB marketplace because we consider it to be a unique case (Yin, 2003), which has experienced extreme growth in a very short time and to date, the most popular platform within the hospitality industry. This design allows us to investigate users' trust perceptions within the real life context, and to develop an in-depth understanding without decontextualizing our empirical material from its sociocultural context (Darke et al., 1998). Further, this design allows us to provide a rich description of the factors driving trust perceptions and how these get communicated through the online review system, drawing from the existing literature but at the same time remaining sensitive to emerging concepts. Against this background, we adopt a bottomup approach following the tradition of interpretivism, where data collection and analysis go hand in hand, and existing literature acts as a sensitising device (Choudrie et al., 2016).

Collection and Analysis of Empirical Material
To ensure data (time and space) triangulation, we collected primary data from Inside Airbnb (insideairbnb.com), an independent website that publishes data from the Airbnb platform. Inside Airbnb periodically collects and publishes large-scale datasets from AirBnB listings, but after verifying, cleaning and aggregating them. An independent perspective was provided by material collected from Trust Pilot (trustpilot.com), a third-party review website.
Airbnb's feedback mechanism has often been questioned for its trustworthiness as it is suggested that it presents only positive reviews. To overcome this issue and to prevent any bias, we used Trust Pilot's data to capture uncensored reviews (Edelman and Luca, 2014;Zervas et al., 2015).
From insidearibnb.com, we focused on and collected data from a single city; namely, Athens, Greece. We opted for choosing a single city rather than the complete collection of AirBnB comments because it would be unfeasible to examine the overall comments for all the listings from all the cities AirBnB operates in using a qualitative lens. Further, we specifically chose Athens over other destinations because Athens is a year-round, popular tourist destination, which has witnessed significant growth in AirBnB listings over the recent years; thereby, offering a rich data set.
Trustpilot.com offered a smaller dataset, which led us to collect all the reviews, irrespective of the destination. From both platforms, we collected data across two periods, January-April 2016 and January-April 2017 for comparison purposes and data triangulation. We filtered reviews written in languages other than English, and we also excluded shorter reviews (less than 10 words) so as to ensure data saturation (Fusch and Ness, 2015). In addition to customer reviews, data triangulation was achieved by collecting and analysing a range of secondary data sources. Such secondary data derived from market reports, and various online articles that allowed us to familiarise ourselves with the firm's policies, interpret its Term of Services, and get corroborating evidence for any claims found within the review comments.
The data was collected and analysed laterally to understand our case study while delving deeper into it, and to realise the point of theoretical saturation after gathering enough data from the multiple sources. It is for this reason that data from a second period were included. For further validation and verification purposes of the secondary and primary data, investigator triangulation was used where two authors worked on the coding of the data. Following their coding, the team of four authors would meet and discuss the findings in order to identify possible discrepancies and arrive at a mutually agreed interpretation (Sarker et al., 2001). This protocol was followed to prevent any bias as two researchers acted as the 'devil's advocate', and questioned the emerging codes and findings, which is a strategy often adopted by researchers (Choudrie et al., 2016). Table 1 includes a summary of our data collection and analysis, detailing the relevant stages.
During the initial stage of the analysis, we proceeded with a preliminary exploration of the data, looking for words and expressions that were viewed to convey trust perceptions. We note here that there were only two among 1265 comments with a direct reference to trust: "don't hesitate to trust Emmanouil for your stay!" (ID: 5952749) and "I highly recommend this flat, they are very trusted" (comment 70149743), while we found solely three with a direct  's (1998) note that one's perceptions regarding another's competence, benevolence and integrity feeds into their trust-related perceptions (knowledge-based trust) and that privacy perceptions feed into trust as well (cognition-based trust). As shown in Table 2, we coded each guest comment along one or more types of trust. For example, comment ID 71597530: "Nikos is a real host and a very friendly guy, easy to talk with and clear to communicate with, before and during our stay" was coded under knowledge-based trust, because the comment suggests that the guest considered their host as person who is benevolent and attentive to their guests' needs, and can therefore be trusted.
Following the extraction of trust, we moved to identifying a preliminary set of first-order themes (e.g., Communication, Hospitality, Unpleasant Interactions). These themes emerged directly from the empirical material.
Next, first order themes were merged together into tightly related concepts, while some were relabelled based on our continued comparative approach to the data and the themes. This resulted into forming our second order themes, i.e., our main categories of Level of Interaction, Information Asymmetry and Support Provision. In the next stage, two of the authors reviewed in consultation the resultant themes in order to ensure that the developed themes reflect the topic of the study, that they are mutually exclusive and that the coding scheme in its totality is exhaustive, thus further strengthening the validity and the rigour of the study (Miles and Huberman, 1994). The final stage entailed the development of the study's chains of evidence (i.e., Table 4 and Table 2 including our first and second order themes, with example narrative for each theme).

Findings and Analysis
In this section, we contextualise the discussion around the identified themes and categories (Table 2). Then, an explanation is provided of how trust perceptions are developed within the particular sharing economy marketplace and how these are communicated via user reviews among the participants.

Drivers of Trust: Information and Interaction
Building trust is seen as a way of minimising perceived risks and their impacts, particularly when the context of interaction is somewhat impersonal (Lai and Tong, 2013). At the same time, trust relates to one's expectations about the other party's behaviour, usually along the dimensions of integrity, benevolence and competence (McCole, Ramsey and Williams, 2010). With these in mind, we analysed the data with the aim of identifying the underlying conditions that that lead to trust development or collapse as communicated through online reviews. While there are many different factors that can be seen as relevant to trust, such as location, room aesthetics and room description among others (Cheng et al., 2019), in this study we have focused specifically on those factors that pertain to communication between guests and hosts because we are interested in identifying on the relationship between the two parties rather than the accuracy and representation matters of listings in the platform. Our analysis showed that the underlying conditions that support or obstruct trust formation and that pertain to the relationship and communication between the two parties are a combination of information asymmetry and lack of interaction between guests and hosts, exacerbated by the provision or lack of support.

Level of Interaction
Based on our findings, users highly valued their host's promptness in responding to requests, prior to and after arrival.
This was because guests viewed them as helpful gestures and evidences of hospitality (Communication, Table 2). For example, a user commented that their host: "is a real host and a very friendly guy, easy to talk with and clear to communicate with, before and during our stay" (ID: 71597530). Similarly, when communication is poor or virtually non-existent, users emphasised this in their reviews ("I messaged Miglen multiple times and had no response at all until over a day later", ID: 65225788). This suggests that maintaining a two-way communication channel, not only before arrival, but also during the stay is important for guests visits and for the host since the quality and the promptness of the communication serve as cues for inferring credibility and integrity (Sparks et al., 2013). This holds even in those instances when guests seem not to have met their hosts: "I never met foris but it felt during our conversations that I can trust him in need. (…) Anyway I recommend Foris's apartment in many kinds." (ID:

62596224).
Next, another important theme that emerged from our analysis is hospitality (feeling unwelcome, felt at home, Table   2). As trust forms when one perceives the other party as benevolent, competent and with integrity (Ridings et al., 2002), being hospitable feeds into one's competency to act as a host; therefore leading to trust perceptions. Indeed, a user highlighted that their host made them feel "immediately at home there" (ID: 58398137) with our analysis showing that users quite often leave cues in their reviews about their host's efforts to make them feel welcome and their own appreciation in relation to trust perceptions: "I highly recommend you take time to visit with them as they have a lot of great insights to share about Athens and Greece. (…) I am happy to refer anyone to Stratos for an accommodation as he is very trustworthy, honest, and friendly. Would definitely stay at his place again." (ID: 69043244).
However, most frequent were the comments highlighting the quality of communication and upon arrival of the interaction between guests and hosts (unpleasant interactions, Table 2). This was evident by users reflecting their host's friendliness, their pleasantness and perceptions regarding their relationship with them. For instance, one user reflected on the hosting and suggested that he "is a real host and a very friendly guy, easy to talk with and clear to communicate with, before and during our stay" (ID: 71597530). As shown earlier, being able to communicate promptly is of paramount importance with users emphasising skills such as, the host is "easy to talk with" being important. While the extreme majority of reviews tended to praise the hospitality of the hosts, there were quite a few revealing less than ideal experiences: "the host became very violent and abusive when I simply asked if their baby was OK after hearing it cry non stop all day. (…) I feel it's very dangerous for anyone to stay at that apartment" (Comment 145). Such reviews are primarily posted in turstpilot.com rather than in AirBnB. However, even in AirBnB's own review system, there are a few instances revealing similar experiences: "Property is good BUT Host and her relatives are a NIGHTMARE to deal with. (…) Not worth the risk." (ID: 66363507). In such instances, users considered it risky to choose a particular host, with negative interactions directly affecting trust perceptions.
Finally, for the theme of level of interaction level, emerging dimensions were privacy and safety. From our findings, it is evident that there were quite a few situations of users feeling uncomfortable, or having their privacy breached by the host "She kept coming to the apartment almost every day when we were not there and touch our stuff. We did not expect that as we booked the whole place and it did not say in the house rules that the host was going to use the apartment." (ID: 69462656). Similarly, another guest discussed that "one afternoon a guy opened the main door and came inside with a Egyptian guy who wanted to stay there in another room. (…) Overall not a very good experience for us and not very safe either." (ID: 71503683). Privacy has been shown to be a direct antecedent of risk, while safety, or security, to be a direct antecedent of trust (Chin et al., 2018). Therefore, when either of these are lacking, trust perceptions are difficult to form.

Information Asymmetry
AirBnB users typically referred to the marketplace's review system (unreliable reviews, impossible to review, Table   2). They criticised the implemented policy of providing a review by the platform as unfair due to not being able to enter a negative posting: ("Even though we stayed a horrible 12 days our booking was cancelled by the host, therefore we were unable to post a review warning others", comment 145). They pointed out that with this system in place "There's no way to give a negative review on Airbnb as the hosts can block." (comment 145). They explained that when a booking is cancelled, neither the host nor the guest can leave a review, regardless of why or when the cancellation occurred. In such instances, the marketplace posted an auto-generated standardised text indicating that one party cancelled the booking; however, this conceals narratives that may be viewed as negative experiences, while it frames the impact of a cancellation in a less damaging manner: "So here we are, already in Florida and trying to find a place to stay during the busiest time of the year. I can't begin to describe my level of stress" (Comment 120).
Within this context, it is worth mentioning that despite the distortion due to the policy, previous reviews were still an integral element for choosing a listing, with users referring back to these in their own reviews in order to signal their agreement or disagreement: "Having read such enthusiastic reviews of this property, we were prepared to be disappointed. Not a bit of it!" (ID: 58398137). It is also worth noting that AirBnB has been forced to change this policy by the UK Competition and Markets Authority (CMA), with effect from August 31, 2017 (Brignall, 2017).
To alleviate information asymmetry, users commented on the accuracy of the listing's provided information and its condition (accuracy of listing, condition of listing, real home, Table 2). For example, a user directly noted that "The description of the apartment is perfect and what it is", further adding that "it is a real home and everything is very convenient and comfortable" (ID: 71597530). Signalling "real homes" versus "professional renting companies" is mentioned often among user reviews ("This apartment is not from a private host, but a professional renting company." ID: 71625285). This is worth noting particularly because AirBnB operates within the sharing economy, and aims to provide authentic tourist experiences, where people can experience a city just like locals and interact with local hosts who "can teach you something new about the culture" (Mildengall, 2017), which is less feasible when transacting with a business (i.e., a hotel or a professional renting company).
A third dimension related to communicating the Terms of Service and the House Rules via the platform (for each listing). Findings showed that the overall quality of the marketplace's website with regards to clarity and transparency is low that prohibited participants from accessing and appreciating the terms of service (rule accessibility, unaware of rules, Table2). A user noted that while seeking new bookings, booking cancellations, or complaints information they are faced with what is perceived to be a poorly designed website ("the website lures you in with affordable looking places that range from $50-80 a night until you view the entire listing and it tells you there's a $30 cleaning fee and $20 service fee. (…) most of these problems occur because the AirBnb website is poorly functioned which can lead you to book the wrong dates and number of guests." comment 174). This comment exhibited an unawareness of the platform's rules, due to an inability to easily access the pertinent information. Cross examining other comments, there appeared to be some consensus that it is quite difficult to locate and interpret information: ("I wonder if Airbnb states these rules somewhere, but they are hard to access. (…) I'm honestly still confused, and their legalese/terminology is hard for me to understand; and, I'm American and speak fluent American-English. The website layout is exhausting and confusing, which is the price they pay for looking flashy and trendy. (…) The rules and expectations are not made clear on the website, at least not for a first-time user; and, their terminology is non-specific and confusing.", comment 95). As a result, information asymmetry endured.

Provision and Lack of Support
While information asymmetry and lack of interaction related to guests' and hosts' encounters, the theme of support provision related to both these groups, as well users' encounters and interaction with AirBnB. If and when users experienced problems, frustration or other types of risks, and when particularly these were extreme, users typically attempted to resolve the situation by seeking support in the form of communicating with their host or directly with the marketplace provider. For example, one guest commented that following their unpleasant interaction with their host, they turned to Airbnb for intervention and support: "Luckily I had receipts of all the sheets, pillows and towels I bought the day I arrived in Athens and was able to win the case with Airbnb." (ID: 66363507). In this case, the marketplace provider acted as a mediator towards an issue's resolution. In other cases, however, the involvement of AirBnB was not as well received because the user evaluated them as being indifferent to their problem ("Airbnb have not taken down the listing even though there was another review complaining about the same noise issue.", comment 145) Understandably, comments pertaining to the conduct and support provision from AirBnB are not published at the platform's review areas. Instead, they were all derived from the trustpilot.com website, with some posts published by hosts, rather than guests. The negative comments in this respect all concurred about the lack of support from the marketplace should any problem arise ("I have been a host on Air B&B for around a year for my beach house. (…) I now discover there is NO ONE at Air BB to talk to or get advice and the only advice I had on their help list was go to the local authorities.", comment 160). In addition, a few of these comments directly related the lack of support to their own personal safety and the platform not being trustworthy: "Airbnb did not ban these guests or even contact them

directly. (…) Airbnb only cares about protecting itself, not you. (…) I strongly advise anyone thinking of hosting to
JUST SAY NO! Airbnb's host guarantee is a scam." (comment 17).
As far as the guest-host interactions are concerned, when hosts strived to accommodate their guests, guests valued it very highly, especially in their times of need, which underlines the importance of support provision: "Our host was very, very welcoming, even when there was a slight miscommunication in our check-in time, she still took care of it and of us and provided us with comfortable accommodation without letting it be a problem!" (ID: 71377792). In many instances, such support seems to be indispensable for trust formation, as guests find themselves in unfamiliar locations.
Most users formally referred to this element when relating the level of support when interacting with one another.

Discussion
AirBnB is probably the most successful peer to peer platform of in the hospitality sector. This was confirmed by the large numbers of reviews on AirBnB's platform and elsewhere, which further suggested that AirBnB is quite successful at matching travellers with hosts (Zervas et al., 2015). It has therefore attracted and continues attracting the interest of worldwide travellers. By doing so, it has made a significant impact on the tourism and accommodation sector (Guttentag, 2015).
In our study, we identified two main conditions that support or inhibit trust; information asymmetry and lack of interaction. The impact of information asymmetry surfaced as a criticism of the review system, where reviews are considered as unreliable, and where the impact and visibility of negative reviews seems to be minimised and controlled by the platform operator. While this tactic partially addresses the impact of negative reviews, which have been found to be more credible than the positive ones (Zhang, 2019), it doesn't tackle the impact the information asymmetry itself.
However, our findings showed that its alleviation lends itself to the formulation of trust perceptions. As shown by the user comments, they don't instinctively accept the reliability of the positive reviews and approach them with scepticism. However, in all cases users actively and explicitly communicated their assessment with respect to the accuracy of the listing, their encounters with the host, the quality of the lodging and that of the neighbourhood, as well as frequently signalling whether the listing is from a renting company or a real home. In addition, on more than a few occasions there were explicit linkages between such comments and trust: "They explained everything and they were very patient. (…) I highly recommend this flat, they are very trusted" (comment 70149743).
The above comment needs to be evaluated considering the complexity of the Terms of Service, and appreciating that users frequently don't even read them (e.g., Milne and Culnan, 2004), or simply cursory glance by them ("I clicked on something at checkout that says I agreed to this policy (despite my not even remembering seeing that), comment 78), both of which further prohibit alleviating the inherent information asymmetry. Most importantly, in relation to trust formation, information asymmetry hinders significantly cognition-based and knowledge-based trust.
Specifically, low quality, unavailability and inaccessibility of information as far as the provider's contact details and service fees are concerned, as well as the terms of service there are suggestions that cognition-based trust is difficult to form. Combined, it suggests that predictability in interactions with the marketplace provider and the other parties will be low, while the insufficient and difficult to parse information will affect knowledge-based trust. This is further supported by a previous study within tourism research that showed trust perceptions relating directly with the quality of the information on travel sites, as well as its reliability (Bonsón Ponte et al., 2015).
Our findings showed that the quality of interaction between guests and hosts was of paramount importance as positive perceptions could lead to future sales for the host and a better relationship between the guest and host. Generally, guests positive reviews signalled trust perceptions and their recommendations for future custom. Positive perceptions included, guests frequently referring to the promptness of hosts with regards to queries, responses by the hosts to the guests satisfactorily deal with, friendliness, and their competence as hosts. Considering that AirBnB and other sharing economy platforms operate on the basis that guests can build new friendships, this is particularly important. However, this relationship relies on the direct experiences of the guest and host rather than the platform. With regards to trust, our findings unearthed the elements that guests communicate within their reviews ("a real host and a very friendly guy, ID: 71597530; "cheerful, friendly and well organized hosts welcoming me with wine and spaghetti (…) very high standard in email communication -definitely 10 out of 10, and remains in touch for any assistance during your stay.
(..) I highly recommend this modern apartment", ID: 70744333). These elements reflect the hosts' competency and benevolence, both of which directly relate to trust perceptions. That is, the guests consider the other party, i.e., the host acting in a benevolent manner (e.g., no misrepresentations, friendly character) and being competent enough to offer their services (hosting) (Pavlou and Gefen, 2004). Finally, the cross analysis showed that the impacts of the aforementioned information asymmetry and perceptions with regards to level of interaction can be further exacerbated when users experience a lack of support from their hosts or the operator. This is especially true when disasters occur. Our findings suggested that support provision is not only integral for positive travel experiences, and therefore reviews; but a lack of it leads to poor interaction and intensified information asymmetry occurrences. The existence of a customer support infrastructure and the potential to successfully interact and communicate with, suggest that when seeking a resolution in adverse situations, a customer can contact their host or at least the provider, which offers assurances and support. In both cases, these aspects relate to trust building, and risk minimising. (Eid, 2011;Srinivasan et al., 2002). Particularly for the sharing economy context, the ability to interact successfully with the provider and receive support from a customer service unit can act as a substitute of other, more formal support mechanisms for building institution-based trust or facilitating cognitionbased and knowledge-based trust. In the case of the AirBnB platform, customer service and support are available through the firm's corporate website and its call centre, which also operates an Emergency line support. Therefore, in extenuating circumstances or simply when additional information is sought (eg. support to contact a host, information on refund policy, among other things), users are directed to one of the aforementioned sources. Yet, as explained, their interaction with customer service is not always considered fruitful while in other cases, this may not even be possible.
We consider that when support is lacking or is insufficient acts as the element that exacerbates user perceptions regarding risk and reduces trust perceptions. In other words, we consider that support acts as a cutting point, which pushes users towards evaluating the marketplace provider fairly negatively and considerations to disengage with them for future travels and business.

Conclusions
Trust is of the outmost importance for sharing economic platforms, as they combine both the uncertainty conditions of online marketplace, with the element of the face to face interaction with unknown others. To date, few studies have investigated user motivation for using such platforms (Lutz and Newlands, 2018;So et al., 2018), their impact on traditional sectors, such as hospitality, transportation, and others (Blal et al., 2018), or for example, matters of listing accuracy, and self-representation (Schuckert et al., 2018). However, studies on trust within the sharing economy are either conceptual endeavours (e.g., Etzioni, 2018;Hawlitschek et al., 2018), emphasise themes, such as reputation and revenue maximisation (e.g., Abrate and Viglia, 2017;Cheng et al., 2019;Tussyadiah and Park, 2018) or focus on the credibility of positive versus negative reviews (Zhang, 2019). To fill this gap, in our study we adopted a bottom-up approach based on guest online reviews towards unpacking trust perceptions and contextualising them in the case of the AirBnB platform.
In this study, we focused on AirBnB's online review system to explore how trust-related perceptions get communicated through the online comments and reviews of the platform's users. Based on our analysis, it shows that the factors that drive trust formation or collapse relate to information asymmetry and quality and quantity of interaction. Furthermore, from our findings we showed that support provision is an important driver, particularly given the absence of a face-to-face interaction. Most importantly we have unpacked three important drivers into their constituents, such as prompt communication, hospitality, and accuracy of listing among others (as shown in Table 2).
This study contributes to research in several ways. We illustrated that the critical conditions that hinder trust formation are information asymmetry as well as the lack of interaction. What is also an interesting implication is that the impact of both of these can be exacerbated when there is a perceived lack of support among users and between them and the marketplace operator.
This study is particularly important for practitioners and the industry. For practitioners, this study not only identifies trust being an important aspect of an online platform, but it also qualifies this by understanding the mechanisms necessary for forming trust. Trust is indeed important, but more so when it comes to the actual experience offered by the sharing economy platform. Then, the platform's Terms of Service provide important provisos, which, if not properly understood, could lead users to experience high levels of perceived risk, as for example in the case of cancelled reservations.

Lessons Learned
Based on our findings, we have identified two particular lessons that can be of value for both academia and the industry. Qualitative feedback can be of direct value to practitioners and more so for existing and prospective AirBnB hosts. In our study we showed that guests comment on a number of things that go beyond the accuracy of the listing, cleanliness of the accommodation and their overall satisfaction with their experience, which is the norm with typical hospitality facilities. These may include comments regarding the provision of maps, tips for local shops, first day supplies and other gestures from their hosts that can be interpreted as a personal touch that enriches their experience.
These review elements cannot be quantified and typically are not included in the metrics used by such platforms; however, they are valued by existing and prospective guests. As a result, such qualitative feedback can help hosts identify which of their actions contribute towards an improved service, and therefore decide whether there is value for money in further pursuing them.

Limitations of the Research
One of the main limitations of our research is that our study is designed around a qualitative case study; therefore, our findings need to be interpreted cautiously. Our findings are not generalisable to other cases, and especially irrespective of their sociocultural context (Darke et al., 1998;Yin, 2003). However, our research aim was not to offer generalisable findings nor develop theory. Instead, our aim was to offer a rich description of what are the trust-related features that get communicated through an online review system. Thus, our findings can be indeed applicable for the understanding of other sharing economy marketplaces with similar contextual conditions (Walsham, 1995); for example, within the hospitality and tourism sector, and where a two-sided review system is in operation.

Identification of codes and themes
Coding of empirical material around first order themes (all codes emerged directly from the data, e.g., Communication, Hospitality -Error! Reference source not found.), and second order themes, where first order themes were grouped together into larger categories, e.g., Level of Interaction -Error! Reference source not found.).

Review of codes and themes
Two authors reviewed the themes, ensuring that the reflect accurately the topic of research, that they are mutually exclusive (no overlaps between codes) and that they are exhaustive (all relevant material coded into a code) (Miles and Huberman, 1994).

Reporting Findings
Final analysis of selected quotes, development of chains of evidence (Error! Reference source not found. and Error! Reference source not found.), revisiting the literature and developing findings. Dorota came all the way to airport to pick us up as we had a late night flight, we were very much pleased with this gesture of hers. Her flat is on 1st floor and the corridors are bit smelly and dark even during the day and you have to put the light on manually. (…) The house needs bit refurbishing as many things seemed old for us. In one afternoon a guy opened the main door and came inside with a Egyptian guy who wanted to stay there in another room. (…) Overall not a very good experience for us and not very safe either. But may be for this money and may be in Athens you can't expect much more than this, but she personally was very helpful with whatever we asked. Thank you very much.
(ID: 71503683) Unreliable reviews Unaware of rules "I've read several of the recent reviews, and notice they are either exaggeratedly positive or negative. While rentals would naturally vary by their location, a lot of the negative reviews seem to be directed at the way Airbnb refuses to give refunds when there are extenuating circumstances (like being scammed). However, I wonder if Airbnb states these rules somewhere, Rule accessibility Unclear rules but they are hard to access. (…) The rules and expectations are not made clear on the website, at least not for a first-time user; and, their terminology is non-specific and confusing. I probably won't use Airbnb again; but, I wouldn't necessarily discourage others from using it" (comment 95) Support Indifferent Impossible to review Unreliable reviews "The response from Airbnb was very good when I called to say that the host became very violent and abusive when I simply asked if their baby was OK after hearing it cry non stop all day. (…) We got out OK but see that Airbnb have not taken down the listing even though there was another review complaining about the same noise issue. I feel it's very dangerous for anyone to stay at that apartment as the host is clearly disturbed and will become hostile if anyone mentions the noise. Even though we stayed a horrible 12 days our booking was cancelled by the host,therefore we were unable to post a review warning others. There's no way to give a negative review on Airbnb as the hosts can block." She kept coming to the apartment almost every day when we were not there and touch our stuff. We did not expect that as we booked the whole place and it did not say in the house rules that the host was going to use the apartment. The apartment is very old and dated. There is no hot water in the kitchen. There are missing tiles in the bathroom covered with sheets of paper and no holder for the shower head. (…) We thought this was very kind of her so we went sightseeing in the morning and came back at 3pm to pack but to discover that somebody had started cleaning already and had moved our stuff. (…) I told her that if she had told us we could have moved out in the morning. She said that she told us but we did not understand (…) She was sweeping the floor around the suitcases and moving our stuff. I wanted to change but I had no privacy. (…) We had such a stressful time. We were very disappointed and we would not recommend this place.
(ID: 69462656) Unpleasant hosts Condition of listing Privacy Value for money Host accused guest Platform mediated

Wouldn't recommend/Risk
Property is good BUT Host and her relatives are a NIGHTMARE to deal with. The Internet was left unpaid on 3 different occasions, the boiler broke down and it took them 2 weeks to replace and I was left with no hot water, the place was not professionally cleaned and the owners sister came and went as she pleased, constantly disturbing my stay. I rented the property for 4 months, i spent over EUR 10,000 and in the end I was accused of stealing a room aroma diffuser and a plastic coffee shaker both worth 7 euros.. Upon replacing them, despite the fact that I had not taken them I was accused of stealing towels. Luckily I had receipts of all the sheets, pillows and towels I bought the day I arrived in Athens and was able to win the case with Airbnb. I will be carrying this matter further however and will be suing for defamation. (…) AVOID at all cost! Not worth the risk.
(ID: 66363507) Accuracy of listing Real Home

Good communication before and after
The description of the apartment is perfect and what it is. (…) Very cosy, it is a real home and everything is very convenient and comfortable. (…) Nikos is a real host and a very friendly guy, easy to talk with and clear to communicate with, before and during our stay.(…) He did not only

Kept informed
Would recommend explain everything where to go, what times and how, but he even guided us through the city with us in his spare time! (…) For example; he texted us when he change our sheets and when we came home after there was a bottle of wine on the table with two glasses (…). We highly recommend this place because of all of this and the location is perfect (…) (ID: 71597530) Importance of reviews Accuracy of listing Felt at home

Helpful host
Having read such enthusiastic reviews of this property, we were prepared to be disappointed. Not a bit of it! (…) The photos do not lie. Much love and care has gone into Maria's loft and we felt immediately at home there. It is also spotlessly clean. The apartment is wonderfully well situated with Plaka's multitude of restaurants and cafes at the doorstep. (…) All of Athen's main archaeological treasures, including the Acropolis (…) As for Maria, she was a warm, welcoming host and couldn't have been more helpful and charming. She speaks perfect English which was very welcome when it came to ordering taxis for us.
(ID: 58398137) Note: Comment number reflects the comment ID number in Table 3 (Appendix), while ID number refers to the review ID provided by insideairbnb.com