A multiplayer-only game has been permanently removed from Steam following the developers shutting down the multiplayer servers. As in, if you had it in your steam library yesterday, you don't have it today. Apparently this is a "first" on Steam. Although people have had their games removed before (scammers, invalid keys and so on) this would be the first time a game is removed for every owner.
I wonder if this is a sign of things to come. Perhaps we've been living in some golden age of digital delivery and only now are we starting to "pay the bill".