Online groups can become communities, developing group identification and fostering deindividuation. But is this possible for very large, anonymous groups with low barriers to entry, highly constrained formats, and great diversity of content? Applying social identity theory and social identification and deindividuation effects theory, this study assesses influences on group identification and deindividuation in the case of Imgur.com. Respondents reported slightly positive levels of the three forms of group identification, but mixed levels of two forms of deindividuation. As argued by proponents of computer-mediated communication, demographics play only a minor role on these outcomes. More involved usage, such as direct access and commenting on images, is more associated with these outcomes, while more basic usage, such as total hours and reading comments, has little influence. Deindividuation is positively associated with group identification.