1. Literally follows a person's every move, on Facebook or otherwise.
2. Is way too obsessed with someone to the point of being a creeper
Iris: At 19:30 EST, she was chilling on the Upper East Side.
Madeleine: Oh my God, you stalker!! BTW, did you know she made $130,000 last year? I bet she was laughing all the way to the bank!
Iris: Who's the stalker now? And yes, actually she was. I saw her.