"Facebook basically takes everyone you've ever met, puts them all in a big jar, and shakes the jar to make them fight. (I'm going to just focus on Facebook here, because nobody's grandma is on Twitter unless your grandma is Michael Ian Black; Google+ is extinct; and if you've ever accepted anyone's LinkedIn request then you just failed the psychopath test.) There is no place in real life where your grandma and your barista and your best friend and that guy you went on two OkCupid dates with are going to sit around and have a conversation about gay marriage. But the entire point of Facebook is to facilitate those kinds of interactions. While you might never bring up messy political issues at Thanksgiving dinner because you know that grandma doesn't trust immigrants or whatever, you don't think twice about posting them publicly on your wall, right where grandma can see them. And comment (the baby Jesus, AIDS, go back to Mexico, etc)."
Yes, that's exactly why I think it's a bad damn idea. Too bad Google+ and it's "hide the circles" thing didn't ocme first and it's too late now (in a sense, though I won't join that one either 'cause I don't want to tie everything in Google to it) Facebook brings together EVERYBODY...and EVERYBODY can't tolerate each other.