Dynamics and diversity of online community activities

Web sites where users create and rate content as well as form networks with other users display long-tailed distributions of user activity. Using data from one such community site, Essembly, we propose and evaluate mechanisms for these distributions that rely only on information actually available to users. For Essembly, we describe the scale-free degree distribution of the social network as a result of users' shared interests, manifested by their content rating activity. We find the long tails in network properties arise from user activity rates that are broadly distributed, as well as the extensive variability in the time users devote to the site.