I think there's a degree of civility brought about by IM, SMS in particular as you normally know the person, or have interacted with them long enough so that yo

I think there's a degree of civility brought about by IM, SMS in particular as you normally know the person, or have interacted with them long enough so that you consider them (and they consider you) part of your 'circle'. IRC - on specialist forums perhaps there is some civility because everyone in that forum is likely experienced and interested, so mutual respect and good manners reign. But when you put together a heterogeneous group of people with no defined clear goal for the group and mix in anonymity by default, you get 4chan. It'd make an interesting sociological study, which factors (privacy, anonymity, interest group, etc.) correlate with aggressive online social groups.