What we're actually building is something more like a cross between a tavern, a opium den, and a public square. People hang out in various random emotional moods, all waiting for something to trigger them into acting like a mob.
I know that sounds like hyperbole, but it's real. We are creating a system for over-reacting in a big way. Sometime -- sometime soon - some innocent person is going to get killed by one of the internet mob phenomenons. It's a miracle it hasn't happened already.
The interesting question is: what happens then? Does the net somehow correct itself? Or do the swings get wilder and wilder, ending up in 2050 or so with little bits of the net attacking little other bits in widely strewn locations? (What would be the term for this? Internet gangs? New nation-states? Niche warfare?)