Abstract: Information Foraging is a theory of human-information interaction that aims to predict and explain how people will best shape themselves to their information environments, and how information environments can best be shaped to people. In recent years, we have been studying social interactions on the Web (e.g., wikis, tagging systems, twitter). I will present models of how people find and make sense of information in social media, as well as models of the population dynamics of contributors in systems such as Wikipedia. Speaker Bio: Peter Pirolli is a Research Fellow in the Augmented Social Cognition Area at the PARC, where he has been pursuing studies of human information interaction since 1991. Prior to joining PARC, he was an Associate Professor in the School of Education at UC Berkeley. Pirolli received his doctorate in cognitive psychology from Carnegie Mellon University in 1985. He is an elected Fellow of the American Association for the Advancement of Science, the Association for Psychological Science, the American Psychological Association, the National Academy of Education, and the Association for Computing Machinery Computer-Human Interaction Academy.