Detecting marionette microblog users for improved information credibility

In this paper, we mine a special group of microblog users: the "marionette" users, who are created or employed by backstage "puppeteers", either through programs or manually. Unlike normal users that access microblogs for information sharing or social communication, the marionette users perform specific tasks to earn financial profits. For example, they follow certain users to increase their "statistical popularity", or retweet some tweets to amplify their "statistical impact". The fabricated follower or retweet counts not only mislead normal users to wrong information, but also seriously impair microblog-based applications, such as popular tweets selection and expert finding. In this paper, we study the important problem of detecting marionette users on microblog platforms. This problem is challenging because puppeteers are employing complicated strategies to generate marionette users that present similar behaviors as normal ones. To tackle this challenge, we propose to take into account two types of discriminative information: (1) individual user tweeting behaviors and (2) the social interactions among users. By integrating both information into a semi-supervised probabilistic model, we can effectively distinguish marionette users from normal ones. By applying the proposed model to one of the most popular microblog platform (Sina Weibo) in China, we find that the model can detect marionette users with f-measure close to 0.9. In addition, we propose an application to measure the credibility of retweet counts.