I've never liked social networks.
Internet Forum systems have always been nice, though. They sort of forced people to have constructive or intelligent to say, or at least had something to say. I use Facebook every few months, and even though I want to catch up with some of my friends who use the service, I can't stand the things they say or the things their friends say. I tried to use it with restricted settings, only displaying some updates and not getting any emails or anything, but it was too much. I saw no status updates because the people I always wanted to hear from didn't use Facebook, and everyone who did shared too much.
That's my main issue, people tend to overshare. Status updates happen often and they're contentless. Either jokes that fall flat (every time) or just a dumb statement to illicit a response. These just upset me. I don't want to talk to someone who lacks the ability of thought and can't create their own worthwhile content, and that's sort of the issue with Web 2.0.
The participatory web is bad because the participants don't need any training, they don't need any thought or even a place to start. They can say anything, no matter what. Take a Youtube comment. YouTube comments are dumb and often offensive, but they're also normally crazy avant-garde statemens. YouTube comments have fallen from being stupid, offensive ramblings to inane crazyness. Seriously, read a YouTube comment and pretend it's relevant.
Facebook is the same way, expect it's all of my dumb friends instead of rando's. YouTube comments I can ignore, but my friends I cannot. I expect more of them. Facebook is a waste of my time because the only thing Facebook can do is waste my time. The issue isn't really Facebook, but the people who use it. The participants aren't willing to be better, because there is no bar for entry. There is no moderation.
Twitter is that, but lighter. The tweets have to be small, so the content is precious. Dumb tweets are a ll around, but tweets are much more selective. No one is forced to see every response, or forced to see freinds of freinds tweets. It's better, but not perfect.
So I'm antisocial.