The act of writing on someone's Facebook wall, poking them, or sending them a Bumper Sticker after seeing them or hanging out with them, often to make light of a joke or incident from the hang-out session. Usually pointless, but creates excitement in the form of a new notification.
Girl #1: Matt and I played frisbee together earlier today, and usually he writes on my wall after we hang out. I'm wondering what I did wrong.
Girl #2: What? No Facebook follow-up?
Mother: Kids these days and their inorganic methods of communication.