when you don't want to talk to anybody on facebook chat but you want to stalk people so you go offline on chat but you still comment and like things.
I was ghost stalking last night because that guy always trys to chat me when I just want to stalk!
(facebook) When one looks at all your posts and quotes them to you in person, but leaves no "like, comment" on your wall at all.
This usually gives you a shock and a sense of insecurity most of the time
"Hey Joe! I see you're quitting swimming" *stunned silence* "Dude. Stop ghost stalking me."