"In Before The Lock": An abbreviation posted to a thread on a web-based forum when the poster knows that any rational debate has long since been abandoned, and will shortly be locked by the forum administrator.
Original poster: Welfare is bad!
Second poster: Oh yeah? Well, you're a nazi!
Original poster: Oh yeah? Well, you're an idiot!
Third poster: IBTL!
Admin: I'm locking this thread. Nothing to see here, move along.