Eh, I think it may come down to Dunbarr's Number more than anything else. People can only have a certain number of truly close friends/connections at any one ti

Eh, I think it may come down to Dunbarr's Number more than anything else. People can only have a certain number of truly close friends/connections at any one time, and when you get beyond that, you see clashes and the social structure breaks down. Maybe Twitter, Facebook, YouTube etc are simply too big, so people break into separate tribes rather than get along with each other.