Proceedings of the 2nd International Workshop on Social Influence Analysis (SocInf 2016) July 9th, 2016 - New York, USA Invited Talk Negative Social Influence in Online Discussions Justin Cheng Computer Science Department at Stanford University Abstract Social media systems rely on user feedback and rating mechanisms for personalization, ranking, and content filtering. However, when users evaluate content contributed by fellow users (e.g., by liking a post or voting on a comment), these evaluations create complex social feedback effects. First, by studying four large comment-based news communities, we investigate the influence of such feedback on future user behavior. How may positive or negative feedback percolate through a community? Next, we focus on the impact of negative behavior (i.e., trolling) on a community - quantifying the effects of both trolls and trolling on the community at large through a combination of experimentation and large-scale longitudinal analysis. Biographical Sketch Justin Cheng is a PhD candidate in the Computer Science Department at Stanford University, where he is advised by Jure Leskovec and Michael Bernstein. His research lies at the intersection of data mining and crowdsourcing, and focuses on cascading behavior in social networks. This work has received several best paper nominations at CHI, CSCW, and ICWSM. He is also a recipient of an MSR PhD Fellowship. 2