Social computing systems are increasingly a part of people's social environment. Inherent to such communities is the collection and sharing of personal information, which in turn may raise concerns about privacy. In this study, we extend prior research on internet privacy to address questions about antecedents of privacy concerns in social computing communities, as well as the impact of privacy concerns in such communities. The results indicate that users' trust in other community members, and the community's information sharing norms have a negative impact on community-specific privacy concerns. We also find that community-specific privacy concerns not only lead users to adopt more restrictive information sharing settings, but also reduce the amount of information they share with the community. In addition, we find that information sharing is impacted by network centraiity and the tenure of the user in the community. Implications of the study for research and practice are discussed.