To define my terms a little, there are two sorts of unpleasant characters here. The first, trolls, are people who are obnoxious for the sake of being obnoxious, because they want a reaction; the second, bullies, are people who are obnoxious in order to get their own way about something. (It doesn't matter particularly about what, and of course in some cases what it's really about is wanting to get their way about getting their way.) The way to get rid of trollish behaviour is to deny the trolls the ability to get a reaction (by banning them, killfiling them, literally ostracizing them, etc.), and that's something that having some sort of moderator with discretionary powers about what gets posted and who gets to post is pretty good at. The way to get rid of bully behaviour is to make it so that being obnoxious is not an effective means to achieve one's goals, and that's the one that's hard.
Slight clarification
Date: 2007-06-07 04:22 am (UTC)-Andy H.