Communication in cyberspace creates the possibility of forming communities of interest that can either compete with or reinforce communities in place. For some individuals, computer networks offer opportunities for greater participation in public life; for others, participation in on-line groups has the potential to diminish commitment to local communities. On-line communities contain unique forms of immediacy, asynchronicity, and anonymity that give them dynamics not shared by communities based on physical presence and face-to-face interaction. These new forms of community, and the technological and cultural resources required for participation in them, have the potential for creating new forms of stratification and hence new barriers to universal access.