SomethingAwful forums still have a fairly dedicated pool of members who post regularly. Some have been on there for as long as 20 years. I remember recently talking to someone who met his wife on there a decade ago.

They're behind a paywall, with reasonably heavy moderation, so people generally behave ok, despite being anonymous. I guess the experience of being muted by a moderator in front of everybody for being an asshole is painful enough that most learn fast not to do that again.

Seems to me that any gated community of "underdogs" is going to attract a loyal following. It's harder to experience the same feeling in a place like reddit, where it's a free for all, there a lot more members, and someone's seniority is less obvious.