Online communities are the fastest-growing portion of the Internet and provide members with information, social support, and entertainment. While a minority, such as Wikipedia, MySpace, Facebook and the Apache Server project are highly successful, many others fail. To be successful, online communities must overcome challenges common in almost all groups, organizations and voluntary associations – solving problems of start-up, recruitment, socialization, commitment, contribution, coordination and regulation of behavior. The social sciences can tell us a lot about how to create thriving online communities. Social science theories can inform choices about how to get a community started, integrate newcomers, encourage commitment, regulate behavior when there are conflicts, motivate contributions, and coordinate those contributions to maximize benefits for the community.

This talk focuses on ways to build members’ commitment to online communities, based on theories of social identity and interpersonal bonds. It provides an overview of the relevant theory, describes results of a 6-month field experiment in which an existing site was redesigned based on principles derived from social identity and interpersonal-bond theories, and describes the results of an agent-based model that examines how different approaches to moderating the content in a group influence social identity and interpersonal bonds.