A consistent theoretical and practical challenge in the design of socio-technical systems is that of motivating users to participate in and contribute to them. This study examines the case of Everything2.com users from the theoretical perspectives of Uses and Gratifications and Organizational Commitment to compare individual versus organizational motivations in user participation. We find evidence that users may continue to participate in a site for different reasons than those that led them to the site. Feelings of belonging to a site are important for both anonymous and registered users across different types of uses. Long-term users felt more dissatisfied with the site than anonymous users. Social and cognitive factors seem to be more important than issues of usability in predicting contribution to the site. Author Keywords Online communities, lurkers, peripheral participation, motivation ACM Classification Keywords H5.m. Information interfaces and presentation (e.g., HCI): Miscell...