On LiveJournal, a community is a forum where multiple users have posting access so they can spread their brainfarts and mental wankage to even more idiots.
Much drama is created in communities, such as:
- Mod drama - created when the moderator tries to enforce their will on the community
- Ratings Communities - a weird community type where you have to prove your beauty/coolness/ability to eat Twinkies to get in
- Abuse drama - where LJ Abuse bans communities for violating the nebulous TOS
- Community deleting drama - where the mod packs up their community and goes home
In a more general sense, the word "community" is often used on the internets as shorthand for "ridiculous circle-jerk," e.g. "the DDR community," "the Buffy community," or "the Harry Potter motor-oil face-rape fic community."