I've only ever used Facebook on one occasions: For a brief time after they opened it up for non edu accounts, at that point it was more or less identical to a German alternative, so there was no good reason to use it because none of my friends were there. I think that account might still be around but is tied to an email address I stopped using soon after. I kind of expected it to remain something used only by college kids and Highschool students, because it facilitates the kind of superficial, gossipy interactions that immature people tend to like.