movie and tv series communities
social networks
blogs
Reddit
mothers communities
people with disabilities communities
MySpace
YouTube
artists communities
music communities
social networking communities
college student communities
teen communities
adults-only communities
Facebook
Yahoo!
scientific communities
books communities
LinkedIn
religious communities
classmates
couchsurfing
Wikipedia
deviant communities
local political activism communities
elitist communities
newsgroups
investing communities
games communities
concepts