Online groups have been described as “virtual communities,” although commentators differ on the amount of group feeling that they observe online. This paper reports on a survey that investigated to what extent people who post to 30 widely-varying online groups experience community online. Results show that two-thirds of respondents did indeed perceive a sense of belonging to their group. Beyond that, dimensions analogous to those of geographic communities were studied, and differences were found among the groups in those dimensions. The best predictors of these dimensions tended to be the time and effort individuals put into the groups. These dimensions added up to a unified statistical “Community” factor. Although the newsgroups did not turn out to vary significantly with this factor, individuals’ experiences in their groups did. For women, their experience could be predicted by the thoroughness with which they read the group; for men, their experience could be predicted by the prevalence of women on the group.