I was really offended at first when people would "friend" me and then never email, or seem to want to catch up. Then I realized, many people will friend even a remote acquaintance. I've had friend requests that I don't recognize; I can discern that I must have gone to high school with them, but that's it. So now I'm embarrassed that at first I was emailing everyone who friended me like they'd sent me a hand-written card in the mail or something. "How lovely of you to seek me out! I'm so flattered!" When really they were just racking up their numbers. Well no more! Now I just accept them and put them on my very limited list (they can see just basic info).