I have gotten many Facebook friend invites lately, from people whose names I don't recognize. Usually I ask them "who the hell are you", but lately I was too overwhelmed even for that. (Overwhelmed by work, mind you. I am not that popular, to be overwhelmed entirely by Facebook invites.
I am trying to keep Facebook for my real-life friends and acquaintances. I also accept friend requests from Net acquaintances, and sometimes from blog fans who are friends of friends, etc, but please, people: if you are not sure I know your name, I probably don't, and if I know you as "blogger X" or "nickname Y from IRC" or "that guy who talked with me at that party and would like to talk again", please mention that in your request. I really don't know half of the real names of the people I meet on the Net.