I deleted my Facebook a while back and I'm happy with the decision.
Myspace was awesome back in the day, like 2005. You could effectively run 'Come over to my place.' game. It was before it got really popular and the media had run their scare campaigns attempting to convince girls that every guy on the website was a stalker. Nobody knew what to make of it, girls would be happy to head over and hang out immediately, something that is rare today. After a few years it became like online dating is now, nearly all thirsty dudes.
Facebook began to lose it's popularity a few years ago. I always considered it stupid, but jumped on the train. At first it was interesting to connect with people I lost touch with. After a while it became an attention whore party with the pics and endless status updates.
I agree with Rosca, there's no privacy. I knew guys who added their bosses to FB, friends who added multiple family members, just idiotic stuff. Basically everything you posted on there became news to everyone you knew immediately. And what if you didn't accept their add? What do you have to hide? They added that limited profile stuff, but still.
Unless I was advertising a business, I don't see the point. I talk to some younger guys, and they say 'Well people don't think I'm normal if I don't have facebook.'
I tell them that will all change once you get past the age where nobody has an identity or understands who they are.