creep is someone who passes all of their free time on Facebook, looking up details of someone they just met, someone whom they may be infatuated with, but this is not necessary.
A Facebook creep knows of all flattering and compromising pictures of a person, as well as where they are, and follows the developments on the person's wall closely, perhaps to spot a lover not mentioned in the relationship status.
Tory spends all of her free time on Facebook when she should be studying. She is a huge Facebook creep.
Curtis: "Tory! Did you see those new pictures of Chris?"
Tory: "Those were up yesterday. I love the one where he was hammered