I mentioned I read newsgroups, and I often wonder what would happen if someone who posted a troll (inflammatory message, the purpose of which is to simply start an argument) was soundly ignored. It's extremely unlikely this will happen because there are always new people and some folks feel compelled to respond - even though the troll is ludicrous. (Typical post: 'I know I shouldn't reply to this, but...')

I think agreeing to ignore, or 'shun' inflammatry messages could happen here, because of the relatively small number of regulars. Or one person could answer and we could allow them to speak for the group. In face-to-face conversation, this happens all the time.