facebook Sniper
That person who starts IMing you the second you log on, like they've been waiting all day for you to finally show up so they can spam you with nonsense.
You log in, and immediately get an IM: "Hey, what's up?", from someone who's been waiting for you all day.
You just opened Facebook, and your IM pops up: "I've been waiting for you to log on.", from a person who's never said anything to you before.
You just logged in, and you get an IM that says: "I know you're online. Let's chat.", from a person who's never talked to you in real life.