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Networks of Gratitude: Structures of Thanks and User Expectations in Workplace Appreciation Systems

Appreciation systems--platforms for users to exchange thanks and praise--are becoming common in the workplace, where employees share appreciation, managers are notified, and aggregate scores are sometimes made visible. Who do people thank on these systems, and what do they expect from each other and their managers? After introducing the design affordances of 13 appreciation systems, we discuss a system we call Gratia, in use at a large multinational company for over four years. Using logs of 422,000 appreciation messages and user surveys, we explore the social dynamics of use and ask if use of the system addresses the recognition problem. We find that while thanks is mostly exchanged among employees at the same level and different parts of the company, addressing the recognition problem, managers do not always act on that recognition in ways that employees expect.

individual message of appreciation, a manager might see recent appreciation sent or received by her team, and an executive might see aggregate reports of praise or thankfulness across teams. The design of these reports implies an expectation that they can support decisions about feedback, promotion, team composition, and team well-being.
In this paper, we identify two fundamental questions for understanding the use of any appreciation system in the workplace: (a) who do users thank, and (b) what outcomes do users expect from participation?
By considering the structure of who users thank, we can evaluate rhetoric from designers that appreciation systems mediate relationships across company hierarchies, as well as concerns that these systems merely offer "democratized kissing up" (Jurgen 2015). In one possibility, thanks might be primarily sent from managers to subordinates, reproducing hierarchical structures of feedback that the appreciation system was designed to supplement. Alternatively, employees could "thank up" to managers to signal indebtedness and perhaps gain favor or "thank across" the company hierarchy, either to their immediate peers or to others elsewhere in the organizational hierarchy.
What do users expect from participation? A thanks message may signal expectations from the parties exchanging thanks, as well as expectations of the managers who have access to reports on employee appreciation. For example, when thanking someone through an appreciation system, the sender may expect the receiver of thanks to feel appreciated while also expecting the receiver's manager to account for the message in an upcoming performance review. Manager involvement or even the anticipation of manager involvement may affect this interpersonal exchange. On the other hand, lack of manager attention is also cited as a major problem for these appreciation systems (Lahey 2015).
To answer these questions, we situate appreciation systems within related research, then describe the genre of appreciation systems, their design rhetoric, and major affordances across 13 systems. We then contribute a case study of over 422,000 thanks records over four years in the Gratia appreciation system, a system designed by employees of a large multinational company and widely adopted throughout the company. We answer questions on who users thank with descriptive statistics and network analysis of thanks between users, comparing its structure to the organizational hi-erarchy. We answer questions about what users expect with content analysis of system logs and surveys of appreciation senders, receivers, and managers.

Related Work Thanks and Gratitude
This study includes analysis of the structural qualities (i.e. social networks) of appreciation that are mediated by appreciation systems. Theories on the structure and nature of thanks offer frameworks for studying behavior on these systems. Expressions of thanks are a signal of informal exchange between two parties that acknowledges a kind of social indebtedness distinct from formal trade or contracts (Smith 1759;Simmel 1950;McCullough et al. 2001). These messages signal that two parties "have now completed a (usually pleasing) reciprocal exchange, and the door is opened to the possibility of new and mutually pleasing exchanges in the future" (McAdams and Bauer 2004).
This condition of social and emotional indebtedness between parties is described by the Stoic philosopher Seneca: "He who receives a benefit with gratitude, repays the first instalment of it" (Seneca 1928). The two-person structure of thanks has been observed in peer resource exchange systems, where users who are unable to generalize their sense of obligation to a wider community share tokens of appreciation with the specific parties who helped them to "lessen uneasy feelings of indebtedness" (Lampinen et al. 2013). Thanks is also usually attached to a single exchange between the parties, in contrast with gratitude, which is more often associated with overall life narratives, or attached to deities rather than people or institutions (McCullough et al. 2001).

Workplace Social Network Systems
Corporate SNS have broadened information seeking within companies (Ingebricson 2010), expanding the ability of employees to find and connect with people outside their immediate teams ), participating in a trend that emphasizes the value of informal social networks in contrast with strict organizational hierarchies (Krackhardt and Hanson 1993;Burt 2004). In addition to facilitating networks of social discovery and support, these systems often expose network activity to managers who oversee employee goals, incentives, and evaluation within the organization.
Companies have been adopting blogging, microblogging, wikis, and SNS to facilitate knowledge sharing about people and ideas across teams. These systems act as a virtual "water cooler" promoting information exchange and relationship formation. In corporate microblogging systems, employees post personal updates, company news, questions, and requests for discussion (Zhang et al. 2010). Users of corporate blogging systems report benefits of communicating "informally," "without bureaucracy," and "meeting people from other parts of the company/outside my circle," as they make posts and add comments. Blogging becomes an "informal mechanism that links disparate, far-flung parts of the organization into constructive contact" (Jackson, Yates, and Orlikowski 2007).
Informal exchanges in the workplace and the networks they form, such as friendship or advice-seeking networks, are known to be important for understanding how workrelated tasks are accomplished (Krackhardt and Hanson 1993;Whittaker, Frohlich, and Daly-Jones 1994). By identifying and understanding these "invisible" relationships, managers hope to gain insight on informal leadership, information flows, and structures of trust. Other research on informal networks within organizations has focused on identifying sources of good or novel ideas, comparing positions individuals may occupy in both the informal and formal structure, and assessing the capacity of informal networks to execute those ideas (Burt 2004). To identify and measure these networks, researchers have examined self-reported relationships (Krackhardt and Hanson 1993), email communications (Donath 1995;Gilbert 2012) and physical proximity (Wu et al. 2008). Appreciation represents another signal of these informal networks.
Workplace SNS are often used for relationship building and "people sensemaking" across organizational hierarchies as users discover and draw conclusions about other employees whom they do not already know ). In these SNS, profile browsing activity supports the creation of new relationships beyond current teams (i.e. bridging social capital) ), while conversation and interaction strengthen existing relationships (i.e. bonding social capital) (Putnam 2001;Steinfield et al. 2009). The separation of these internal workplace systems from public SNS and microblogging platforms is important to many employees; in one longitudinal study, employees reported resistance and skepticism about the use of public SNS to share information among colleagues (Archambault and Grudin 2012).

Recognition and Incentives in Informal Networks
Systems for informal information sharing and relationship development may operate in tension with formal management structures, which are not always able to acknowledge or reward activity in informal networks. For example, several studies on the failed adoption of computer-supported cooperative work systems cite a lack of recognition or incentives as one major risk to system adoption (Hasan and Pfaff 2006). In one company with an "up or out" promotion structure, where cooperation among employees was not included in promotion review, employees avoided information sharing software (Orlikowski 1992). Concerns that cooperation systems "undermine management authority" can even lead to managerial resistance (Grudin 1988). To address this tension, Grudin argues that systems should offer distinct functions for individual contributors, managers, and executives, in ways that are compatible with incentive structures and the social conventions of teams (Grudin 2004).
The genre of appreciation systems addresses the incentives problem in informal cooperation by combining peer incentives with the hierarchical management structure, supporting all three of Grudin's suggested audiences for successful workplace cooperation systems. When an individual contributor sends or receives appreciation, they support each other through the informal relational network. At the same time, their managers can see the appreciation and incorpo-rate that information into review and promotion processes. Appreciation systems that generate team-level reports offer summaries that can be skimmed by executives, who cannot review each appreciation across all their teams. Since appreciation systems make thanks visible within informal and formal structures, they have possible formal outcomes beyond the informal relationships between people as managers and executives view these reports.
Despite this potential, the use of an appreciation systems in a specific workplace only addresses the recognition problem if two conditions are met: (a) if the structure of appreciation represents exchanges that managers wouldn't see otherwise, and (b) if managers incorporate peer recognition into decisions affecting their teas. By asking who people thank and what people expect from their use of appreciation systems, this paper observes the applicability of these systems to the recognition problem.

Appreciation Systems Defining Appreciation Systems
To describe the genre of appreciation systems, we present an overview of publicly-documented systems. Our initial set of 55 potential systems was created by reviewing over 150 English language news articles and press releases, reviewing feature descriptions of corporate SNS, and asking designers about competitors. 1 Systems were retained if they featured peer appreciation and also made appreciation visible to managers. Systems were excluded if they were not designed for the workplace (i.e. Wikipedia's peer thanks system), if appreciation was purely private (i.e. workplace e-card systems), if only managers could send appreciation (i.e. performance review systems), or if full public documentation of features was unavailable. Of the initial set, we focus on the 13 appreciation systems included in Table 1.
Our term "appreciation system" is chosen to reflect these inclusion criteria and connect these systems to scholarship on the exchange of thanks. We also considered the term "gratitude systems," but this term is inconsistent with theory -gratitude is an affect rarely attached to a specific exchange (McCullough et al. 2001). Other terms like "thanks systems" and "peer incentive systems" over-emphasize the peer aspect of these systems or over-emphasizes a single theory of motivation. "Appreciation systems," is fruitfully ambiguous. It can include both interpersonal appreciation and formal appreciation from one's manager in a wide range of forms: a private note, a bonus, or more public praise.

Technical Affordances of Appreciation Systems
We present in Table 1 an overview of the technical affordances of appreciation systems. While all systems in the table make appreciation visible to the receiver and to managers, they still vary widely in the audience and visibility of appreciation. In some cases, appreciation is associated with a worker's SNS profile page, while other systems place individual appreciation on a "wall of fame" or "Thank You Board" (Munson, Rosengren, and Resnick 2011). Physical 1 Press releases were discovered through PR Newswire. display systems sometimes show a team's aggregated appreciation rather than individual thanks (Yoon 2013).
Not all appreciation systems support interpersonal thanks, which is described as distinct from feedback. While feedback can often be included in the text of an appreciation system, many systems allow managers to structure participation by requiring appreciation to include ratings in the categories used for worker performance reviews. Descriptions of feedback affordances emphasize appreciation given for work-related activities within a formal performance review system. In contrast, systems that promote thanks encourage users to share appreciation for anything that might prompt thanks toward the recipient. In some systems, peer thanks and peer feedback affordances are distinct from each other.
Beyond feedback, another way to quantify appreciation is to award points or credit to receivers. In many cases, these points are exchanged for rewards on an online store, associated with bonuses, or accumulated towards charitable donations. In other systems, appreciation points are associated with badges or other forms of quantified reputation on a corporate SNS. Reporting and analytics systems vary widely across appreciation systems, depending on the details of thanks, feedback, credit, reward, and badges. Most of these systems offer aggregated worker and team level reports, as well as API access.
Many appreciation systems offer affordances for moderation, which allow managers or other moderators to approve or remove messages and bonuses. The designers of Google's GThanks peer bonus system initially avoided implementing moderation affordances, on a matter of principle of trust for employees (Bock 2015). In addition to moderation, many systems, whether or not they offer rewards, include limits and budgets on the thanks or credits that any worker can send.

Design Rhetoric of Appreciation Systems
In press releases and official blog posts, the design rhetoric for appreciation systems often focuses on highlighting unacknowledged contributions among peers. In promotional material, Bonus.ly argues that "peers often reward an activity that would have gone completely unnoticed by managers" (Quinn publication date unknown). In their FAQ page, the designers of Gratia explain that "recognition of achievements (especially when cross-group) doesn't have the right level of visibility," a problem that Gratia is intended to address. Well-being and team bonding are also common design rhetoric for appreciation systems. Designer Ilwon Yoon, creator of the Thanks Duck, argues that appreciation is a deep human need, and that the duck is intended to "create [a] more collaborative and cooperative environment" (Yoon 2013).

Top-Down, Informal, and Piggyback Deployments
A wide range of workplace appreciation systems have been introduced in recent years through top-down and employeeinitiated deployments, as features within existing corporate groupware, standalone systems, or "piggyback" deployments. Among top-down systems, Yammer added a "praise"  Table 1: Affordances of workplace appreciation systems feature in 2011, inviting users to choose a "praise badge," enter a message, and share their appreciation for individuals and groups (yammer 2011). In the peer bonus system Bonus.ly and Google's GThanks, employees are allocated budgets to reward other employees with praise and monetary bonuses. Depending on corporate policy, receivers may be paid directly, redeem bonuses in an online store, or in some cases, choose which charity will receive their bonus (Naziri 2013;Quinn publication date unknown;Bock 2015). Although these systems are typically introduced by managers or HR departments, appreciation systems have also been developed and introduced informally by employees.
The Gratia system we examine in this paper is a websitebased appreciated system that was developed internally by a group of employees who wished to foster gratitude in the company. This system, which we describe in greater detail later, shares thanks messages among employees via email, which are shown to managers in digest form.

Case Study: The 'Gratia' Appreciation System
In this paper, we examine the use of 'Gratia', a workplace appreciation system. Gratia was developed as a grassroots effort by employees of a large multinational corporation who wanted to foster a culture of greater gratitude and apprecia-tion within their company. 2 The system was later adopted by the I.T. department of the company and embedded into other systems, such as the internal people search engine.
The company has a well-connected and geographically distributed workforce of nearly 120,000 people that actively uses a myriad of communication technologies: from email, to instant messaging, to video conferencing, to an internal social network site. Despite all those communication channels, 'Gratia' provides a single-purpose channel for thanks and has maintained an active user base. The company's workforce is clustered in a handful of large hierarchical organizations. These organizations were historically independent from one another, but in recent years have undergone a cultural shift towards more interdependence and collaboration. The organizations that make up the company have teams across multiple building and campuses around the world. Given the nature of 'Gratia', it is worth noting that typically employee yearly reviews are performed around June, while bonuses and promotions are distributed around August.
In the subsequent sections we explore the 'Gratia"s user experience, system usage, and social network of apprecia-tion, with an analysis of system logs and user surveys. We focus our work on the structure of who users thank and what they expect from their participation.

System Overview
To send thanks, employees visit the Gratia web application and create a thanks message that is sent to the receiver via email. Company managers receive weekly digest emails describing all appreciation sent and received by their teams, as illustrated by Figure 1(a). Using the Gratia website, as seen in Figure 1(b), anyone in the company can enter the name of a manager and see the thanks sent and received by that manager's team. Per-employee information is accessible via an Application Programming Interface (API) which has been integrated with other systems in the company, such as a contact directory, a mobile app, and a manager reporting system. The user flow of the system is described in Figure 1(c).
In Gratia, each employee is allocated a budget of two thanks per week. Thanks in Gratia have no formal companywide association with bonuses or other reward mechanisms, although managers may incorporate information from thanks messages into employee reviews. In internal communications, Gratia is described as a "peer recognition system" to help employees "recognize helpful peers across the company." These communications explain who receives notification emails, what messages are visible across the company, and how thanks are aggregated for individuals and their managers.

Data and Methods
As part of our investigation of Gratia, we analyze usage logs -approximately 422,000 records representing all thanks messages sent via the system over the four years from May 2010 to March 2014. These records include information identifying the sender and recipient of the thanks message along with the message text. Each record is timestamped. We combine Gratia system log data with metadata about receivers and senders, that includes department name, job title, and manager. Managers are included in the data if at least one of their subordinates sent or received a thanks message during the observation period. While Gratia usage logs represent longitudinal observations of thanks, employee records are sampled at the end of the observation period.
In our analysis we take a descriptive and relational approach to address: (1) who do users thank, and (2) what do users expect from participation? To address the first, our analysis focuses on features of the informal social network revealed through the act of sending a thanks message to a co-worker using the Gratia system. Gratia's network has just over 80,000 nodes (senders and receivers) and approximately 422,000 ties (thanks messages) 3 . Each node represents an employee; a directed tie from node A to node B exists when user A sends a thanks message to user B.
Managerial data from employee records allows us to construct a second network capturing the formal, organizational hierarchy -who manages whom. This organizational net-3 Statistics are approximate to help maintain confidentiality. work takes on a strict tree structure; each employee has one and only one manager. 4 To explore user expectations, we administered via email a short survey 5 to Gratia users. We construct a stratified random sample based on interaction types, defining the sample strata by whether the participant has exclusively sent thanks messages, exclusively received thanks messages, or has sent and received thanks. We separately administer a survey to managers whose team members had interacted with Gratia in any form (senders and/or receivers).
Our sampling strategy was designed to ensure participants had diverse interactions with the Gratia system, both in terms of the sender-receiver experience, as well as in their tenure on the system. We recruited participants who might have used the system a few years prior to the survey, as well as some who might have used Gratia only a few days prior. Although it is possible that participants' memories regarding the system might fade over time, the system is well-known in the company that at least awareness and opinions about were available. It is possible participants' opinions regarding the system might have changed over time, though, but we considered diversity of tenure to be more important to get a sense of the views about the system across time.
We obtained 29 responses from thanks senders, 6 44 responses from thanks recipients, 7 and 15 responses from managers; yielding a response rate of 11%, 17% and 0.6% respectively. Response rates were low, but we believe responses provide valuable qualitative insight for this study. Low response could be due to turnover in employees since we did not restrict the sample to recently active employees.
User surveys were designed to gain additional insight into user motivations and concerns. The questions were mostly multiple choice, with a few open-ended questions coded manually by the researchers. Specific questions were asked about how users first heard of Gratia, about users' understanding of the general operation of the system, as well as about user reactions to incorporating thanks into formal performance reviews. Survey participants were also asked to reflect on preliminary findings (discussed in detail in subsequent sections) on the social norms of the system. Survey responses, which are presented in later sections, were analyzed by the authors to gain an understanding of common patterns and themes.
While some survey methodologies seek answers on individuals' experiences, our approach explicitly focused on how participants imagine their experience in context of the wider use of Gratia, which is why we also asked users these more generalized questions, such as why people higher or  lower in the organizational behave in certain way, rather than asking the survey respondent to answer only about their experience. We begin our analysis with a short description of adoption and usage patterns over time to gain a basic understanding of the system itself; we go on to quantify structural features of the informal network of thanks and its relation to the formal company hierarchy to address the question of who do users thank. Finally, we incorporate qualitative data from the user survey to support interpretations and implications of the results. We make use of the sna package of the R statistical computing platform and Dato GraphLab Create 8 in our analysis.

Messages on Gratia
Although messages on Gratia are shared with both the intended recipient as well as managers, they typically employ a personal tone and context: 9 • "Thank you for the help you provided over the past few months in answering questions in easy understandable way. You are the best communicator in the team" • "Thanks Carl, You INSPIRE me! I wish the best for you, as you always said, I'm just an IM away!" • "Great job with rocking the project since you been here, don't get discouraged with the things you cannot control. Stay motivated!" • "Thanks for all the great work on the FooBar. I learned a lot working from you on it!" • "Alex, thank you for all your help in getting the foobar created. You went above and beyond to help." The topic and purpose of appreciation messages ranged widely across feedback, encouragement, social value, and reciprocity. Likewise, in surveys, receivers reported that their appreciation messages were mostly in relation to a specific event or task (93%), with over half reporting a general 8 http://dato.com/products/create/overview.html 9 Examples have been slightly rephrased to preserve anonymity, but are consistent in tone and style to the original. sense of appreciation (59%) and more than a quarter identifying appreciation for a specific favor (46%). When asked what they hoped to achieve by sending appreciation (Figure 2), most senders (76%) hoped to "show that you value them as a person." Many users (38%) hoped to offer feedback, while nearly a third saw themselves as paying an obligation or promising to reciprocate in the future.

Descriptive Analysis of Adoption and Use
Thanks messages were sent by over 47,000 unique senders to over 73,000 unique receivers. A total of just over 80,000 unique company employees had engaged with Gratia at the time of our observation. Figure 3 shows (a) the average number of Gratia messages sent per day, (b) the number of unique senders per day and (c) the number of new versus repeat senders per day over the period of observation. The data show increasing use and adoption over time. The pattern of messages sent and unique senders over time are steadily increasing across the entire observation period. In Figure 3(c) we also see both consistent recruitment to the system and retention of users over time. New users join at a relatively constant rate, while the number of repeat users increases over time. Together these figures illustrate a clear pattern of increasing use, without any evident signs of leveling off.
While senders of thanks messages primarily report (in survey data) learning about Gratia via word of mouth (62%), managers and receivers of thanks report learning about the 11 Margin of error on these responses in approximately 3-8%. system almost equally by word of mouth and receiving a Gratia notification. 41% of receivers report learning about it from a notification, and 39% report word of mouth; 46% of managers report learning about it by receiving a notification, the same percent as word of mouth. These word of mouth recommendations may have come from managers; 54% of whom report encouraging their teams to use the system. Email signatures were another way users learned about the system; 8% of managers, 11% of receivers, and 14% of senders reported learning about Gratia from email signatures that linked to the system, like "Was my response helpful? Consider sending me a Gratia."

Who Do Users Thank?
Users have the opportunity to express appreciation via Gratia to any of their co-workers, be they managers, peers or the company CEO. In practice, social norms are likely to structure thanks. We begin our investigation of thanks by considering the extent to which users thank back; reciprocity is a common social norm found many social systems. There are three potential relationship configurations that could exist between any pair of employees or dyad: no relationship, a one-directional (or asymmetric) relationship, or a mutual relationship. 99.9% of all Gratia dyads have never interacted there therefore have no relationship. We also observe that there are twice as many asymmetric pairs as mutual pairs, 0.006% and 0.003% of all pairs, respectively.
To explore mutual relationships, we compare reciprocation against the baseline chance of a tie, taking the relative log-odds of a tie given a reciprocation, versus the baseline probability of a tie (Butts 2008). This is a more appropriate measure of reciprocity in large, sparse networks when relationships have low probability. We find that thanks messages are 9 times more likely to be sent between a pair in which a tie already exists, than between a random pair.
Despite strong reciprocity norms, 80.4% of connected pairs in Gratia only interact once (i.e. exchange one message). On the other extreme, one employee pair exchanges 68 thanks messages over the observation period. This pair are peers, both working under the same manager. For other employees who use Gratia and thank each other repeatedly over time, only 5% of pairs interact 3 or more times. In terms of the lifespan of relationships between pairs, the average time between first and last interaction is 231 days. On aver-age individuals wait 124 days between messages, just over 4 months. When asked about the four-month interval between thanks in free-text questions, most senders were unsure. 17% of senders argued that reciprocating thanks was not necessary. One sender explained that "they aren't doing it just for reciprocation, but genuinely -and it may take time for a genuine need for returning Gratia to occur." Aside from thanking someone back, how likely are users to exchange favors and other forms of support? Among senders, 31% reported using Gratia messages to confirm that they would be willing to help the receiver in the future (Figure 2). We asked senders to rate how likely they were to do a favor from someone they thanked on Gratia, from "as likely as a request from anyone" to "only if I've sent them appreciation," and 65% reported that they would be more likely to do a favor for someone they sent appreciation.
Appreciation Within and Across Teams Next, we investigate correspondence between the informal Gratia social network and the formal, organizational network of managerial relationships. One of the primary motivations for analyzing these two representations of relationships in the workplace is to explore the structure of thanks expressions within and across teams.
To do so, we consider two measures of the formal "distance" between the sender and receiver of a thanks message, each measured in the organizational hierarchy network. The first metric -which we call organization distance -computes the length of the shortest path (a sequence of existing ties in the formal company network) between the two individuals. Since the organizational network is a strict tree, this involves tracing up the organizational chart from the initiating employee to a common authority and then down to the thanks recipient. The second metric -which we call hierarchy distance -computes the difference in the sender's and receiver's level in the hierarchy; level is measured as steps below the top of the organizational tree, i.e. steps from the head of the company (again a step in this case is a managerial relationship).
To identify within-team and cross-team appreciation, we use the number of steps in the organizational hierarchy required to find a manager that has authority over both the sender and receiver of the Gratia message. This is the organizational distance between two employees, as described above. Two employees with an organizational distance of 2 would be coworkers, reporting to the same manager. Pairs with an organizational distance of greater than two would indicate coworkers in different teams.
On average, the distance (path) between the sender and receiver of a Gratia message is 7.7, meaning that thanks messages are rarely sent among members of the same direct team. We find that only around 10% of Gratia messages are sent to fellow team members (a colleague with whom the sender shares a manager), reinforcing that thanks in Gratia are typically send to coworkers outside of one's own team. The use of Gratia across teams is consistent with survey results as well. In free-text replies, a commonly cited reason for sending messages ( Figure 5) is the physical distance between sender and receiver.
Upstream, Downstream, and Peer Appreciation Are Gratia messages more likely to be directed from manager to subordinate (downstream), from subordinate to manager (upstream), or between employees at similar levels? To investigate this question, we use the hierarchy distance metric, described earlier. The average difference in the hierarchy distance or corporate level between sender and receiver is 0.0, implying that Gratia messages are primarily sent to peers of the same level. If more managers were sending appreciation to team members or their teams were sending messages to their managers, the distance would be closer to 1.0. We illustrate this result, as well as the previous on organizational distance, in Figure 4, showing the local, informal Gratia network and corresponding organizational network for two focal participants. In combination these results could suggest that appreciation systems like Gratia help to facilitate an expression of thanks when distance (physical or social) separates individuals who are at similar levels in the company.
(a) Local Gratia network (b) Formal hierarchy Figure 4: Local Gratia network for illustrative thanks message, sent between the two red nodes, seen in (a). Other employees who have also sent or received a thanks message to/from these focal individuals are shown in blue. Path between the two focal individuals (red) in the formal organizational network shown in (b). Blue nodes represent all direct managerial relationships of focal individuals.
When senders were asked in free-text questions why upstream appreciation was uncommon, most respondents were unsure, although 21% of senders cited possible negative out-comes for public, upstream appreciation. For example, one respondent wrote that "Gratia is public and it might be seen as 'asskissing' :)." Likewise, other respondents mentioned this might be perceived as "brown-nosing.' Senders were mostly unsure why downstream appreciation was uncommon, but we can presume that managers might not send messages in a system whose primary feature involved resending copies of their own appreciation back to them.

What Outcomes do Users Expect from Participation?
Users report a variety of reasons for expressing thanks via the Gratia system. User-reported motivations for use, seen in Figure 5, often revolve around visibility and formalization. The primary reported reason for using the system was that the recipient's manager would also be notified of thanks. 12 Figure 5: User survey responses when asked about reasons to use Gratia rather than thank in-person.
Not everyone, however, realized what managers could see. In response to multiple choice questions, 87% of receivers agreed that their immediate managers could see the messages they received, but 52% of senders were unsure if their managers could see the messages they sent. This uncertainty among senders about who sees their messages is reflected in their expectations of the personal outcomes of sending appreciation. Among senders, only 14% expected that sending appreciation would benefit their performance review, and 76% expected that it would not do so. More receivers believed that senders would gain benefits too; 30% of receivers expected that senders would experience benefits to their performance reviews, with only 46% disagreeing.
Do managers actually see these messages? Managers whose team members send or receive appreciation tend to encounter Gratia messages through email notifications. 12 Open-ended survey questions were categorized by two independent coders after a mutually agreed upon coding scheme was developed. The coding scheme was developed via an iterative, grounded approach. Categories were determined by examining responses and expanded when necessary. Each codes then applied the codes to the entire set of responses independently. Inter-rater reliability measure shows higher level of agreement, with percent agreement over 89% for all codes and Cohen's Kappa values for each code of at least 0.60 (majority over 0.80).
Among managers, 54% report reading the email notifications, but only 8% report visiting the system website. Less than half of managers report being aware of exactly how many Gratia their team members receive.

The Role of Appreciation in Manager Decisions
Managers use appreciation information to support employee feedback, promotion decisions, team formation, and performance reviews. 61% of managers who received notifications report incorporating appreciation into decisions affecting their team members. Out of these, the most common use was offering feedback to team members (54%). A small minority of managers report incorporating appreciation into decisions about team formation (8%) and promotion or restructuring decisions (8%). 39% of managers report not using this information for any decisions. Sender and receiver's expectations of direct performance review benefits may have been overly optimistic. While 57% of receivers expected that their performance view would be affected and 62% of senders expected the same, only 15% of managers report incorporating the information in performance reviews. Gratia did bring other, reputational benefits to senders and receivers: many managers (77%) do report discussing appreciation received by their team members. 31% have mentioned it to the receiver, 23% have mentioned appreciation to a third party, and 23% have mentioned a Gratia message to their entire team.
User beliefs about the influence of Gratia on manager decisions is reflected in system usage patterns. As with most communication behaviors, expressions of thanks demonstrate seasonality. Figure 6(a) shows the distribution of messages sent by day of week; use is characterized by an increase in activity at the end of the work week, Friday in particular shows high rates of thanks sent. As one might expect, expression of thanks drop during weekends. Figure 6(b) shows the distribution of messages sent by month of the year. Fewer messages are sent during summer months. Highest rates of messages sent occur in February and March, coinciding with the period before employees' performance appraisals. When asked about these monthly patterns in freetext questions, most senders had no explanation. However, 24% reported that more Gratia were likely sent in advance of mid-year performance reviews.

Rewards and Bonuses
We asked senders "what are your thoughts about using a system like Gratia to influence rewards or bonuses?" and coded responses for positive, negative, or no answer. Senders were overall in favor of using a system like Gratia to give rewards, with 59% in favor and 31% opposed. One person even suggested a specific dollar amount: "$10 per 1 Gratia received, $5 per 1 Gratia sent paid monthly." However, most responses came with caveats, such as "should be considered but not the only factor." The senders who were not in favor of linking Gratia to compensation feared abuse, and losing the wholesomeness of the system: "if you add money to the mix, you will encourage gaming. There is something refreshingly pure about the Gratia system -whether getting or giving, the currency is pure appreciation, which is rare."

Discussion
In this paper, we identify the growing genre of appreciation systems, workplace messaging and microblogging systems that mediate and track expressions of appreciation. We describe and compare the design affordances of 13 of these systems. In addition, we conduct a case study of survey responses and user logs of 422,000 appreciation messages sent within the Gratia system over four years. Appreciation systems are in part designed to address a wide problem of recognition. These systems can only address that problem if the thanks on those systems is exchanged between workers across teams, where managers can less easily observe their work. In our case study of Gratia, we ask if these systems follow hierarchical feedback structures, "democratize kissing up," or reach across teams. We find that thanks messages are typically sent to coworkers outside of one's own team, and that they are sent across the company hierarchy rather than up or down it.
Although usage of Gratia satisfies the structural requirements of a response to the recognition problem, our survey results suggest that it may face its own recognition problem. Users report manager visibility as the main reason for using Gratia, and most managers do report seeing the messages and mentioning them to team members. However, while users had high expectations for the effect of their messages on manager decisions and even sent more appreciation close to the performance review period, a large minority of managers ignored appreciation reports and did not use them to inform decisions. The majority of managers, who did incorporate appreciation into their decisions, mentioned Gratia in feedback or conversations rather than performance reviews or promotion decisions.

Conclusion and Future Work
This paper offers an overview of the appreciation system genre and focuses on quantitative analysis of logs and surveys for a single system. We have described the structure of thanks and user expectations in a case study of Gratia, a system used within a large multinational corporation. The observed high, and growing, use of the Gratia system may represent a gap in the social affordances of messaging and SNS systems already used in the company. Thanks systems may be especially useful to mediate gratitude among distributed teams working on large projects, for whom in-person thanks might be less possible. Care should be taken however, when incorporating thanks messages into employee reviews, to account for the patterns of thanking in relation to the organization chart, and the lack of thanks between direct peers.
Future research could attempt to replicate our findings across multiple companies and different appreciation systems. Other studies could if sending or receiving thanks have an effect on well-being, productivity, chances of promotion, or employee retention. Other research could compare the effects of reward and badge systems to those that do not include rewards. Qualitative research with workers and managers may yield contributions to theories of relation work and offer further nuance to the choices, rationales, and tradeoffs associated with the affordances we have identified. Finally, for corporate SNS that have added appreciation features after initial deployment, researchers may find natural experiments for estimating the effect of peer appreciation on the recognition problem in the adoption of these systems in the workplace.