Imo it's more like the plot of GITS:SAC.
But back to op, you can't compare chans to facebook. FB is just wanking contest with your friends, as LJ or MS used to be, maybe even ICQ/MSN before that.
Twitter is a celebrity circlejerk of which youtube is only half, the second part being kinda chan (the comments. THE COMMENTS!) for average joes. Reddit started as a nice improvement over digg, but will eventually meet the same end - drowned in it's own karma swamp.
Multiple personas is a natural thing. You talk different in school, to your parents and to your friends. But chan is the only place where you can pretend to be anyone you want.
But indeed herd behaviour dictates it all. Chans are the only herd which is not tightly controlled by shepherds, one may say, they/we're a feral bunch.