warpus
Sommerswerd asked me to change this
When you unfriend someone they will notice if they search for you & find you not having "friend status". Or if you block them they won't be able to see your profile or anything you've posted at all.
Or they could have a plug-in that tells them when someone unfriends them right away.
It doesn't mean "I'm not your friend" though, just because FB want to call it that, it just means "I don't really have any interest in seeing the stuff you post on this particular website".