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Detecting tip spam in location-based social networks

Location Based Social Networks (LBSNs) are attracting new users in exponential rates. LBSNs like Foursquare and Gowalla allow users to share their geographic location with friends, search for interesting places as well as posting tips about existing locations. By allowing users to comment on locations, LBSNs increasingly have to deal with a new wave of spammers, which aim at advertising unsolicited messages on tips and comments about locations.
 In this paper, we investigated the task of identifying tip spam on a popular Brazilian LBSN system, namely Apontador. Based on a labeled collection of tips provided by Apontador as well as crawled information about users and locations, we identified a number of attributes able to distinguish spam from non-spam tips. We leveraged our characterization study towards a spam detection mechanism. Using a classification technique, we were able to correctly identify 84% of spam tips and 91.8% of non-spam tips. Our results also highlight the importance that places and related user activity have for detecting tip spam on LBSNs.