At least in my circle, Facebook is this giant dominating force that is second only to our actual physical interaction with each other every day. If somebody says something, takes a picture (especially an
incriminating picture) or takes a movie, at least two people go "FACEBOOK IT!" immediately following the event. And the reverse is true also: people share things found on the internet (esp. viral vids) and share them via Facebook, and less than 24 hours later it's being quoted and/or sung all over the music building. Maybe it's a musician thing

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MySpace is not even half as popular, probably because Facebook used to be college-only, so the people I'm around most often started using that first when they were freshmen (now all are about juniors-seniors). I always used to keep my MySpace-Facebook lives separate, because my MySpace people were all the ones not in college back home who couldn't have a Facebook account. There's a bit of drama with the Top Friends thing, though. One of my friends got into a huge not-talking argument and her boyfriend took her off of his Top 8

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And yeah, it reminds me a bit of high school. Oh well.
It's also a good way to keep up with old friends, as Sass said.
Jam it back in, in the dark.