Community is, obviously, all about self identification. I think it's also important to acknowledge that just because you feel you are in a particular community doesn't mean you are beholden to follow - or even like - other people in the same group. Am I in a community with Cory Doctorow? Yes. Do I agree with everything he says - hell no. When I was half my current age I though that "geek" was it's own singular culture (rock music, role playing games, SF, tech, specific ways of dressing, etc). The pony-tail I've sported for over 30 years was a conscious signal to people that I was part of that group. As I've grown older I've become aware that in reality things are much more diffuse and fluid. Unless there is some kind of gate-keeping (required approval, sign-up, payment, etc) then, like gender, someone is a member of a community if they say they are. I'm a proud geek and very proud member of the global civic tech community - but I don't pretend to have any say over who else fits into either of those categories and no-one else does either.