Despite my initial feelings about Facebook, I find it a handy tool to keep up with old friends that don't go to the same chatroom, and many of the franchises I follow have regular updates so that I don't have to travel to a bunch of different sites or fill my browser with RSS feeds.
Farmville and similar is annoying but you can generally block them. Really, the trick to using Facebook is to steer clear of the apps.
Since I make no effort to hide my real name, I'm sure just about anyone I am acquainted with over the internet could try to add me, but I won't add them (or keep them) unless I know that they know me. I have a few IRL friends of friends but other than that, that's it. And even these might end up getting blocked considering most of them are just on FB for Farmville.