In the case of Facebook, actually someone can add you as a friend but you have to confirm/approve it. And, when it comes to your profile, I think you can manage who can view which. Don't get me wrong, I am not a Facebook fan either.I don't have the time and I don't like to hang out on social networks, although I have a profile on facebook. I don't like how random people can add you without no reason and see your personal stuff.
Good point. I am not so excited to reconnect with old friends either. I even think that bullies in schools could continue to bully their old victims through Facebook.All these newfangled social networks make it so people can't ever get away from the people in their past. One great thing about getting out of high school was getting away from kids who were there when you made every mistake in the book.