2 Steam updates overnight.

The first fixed a crashing bug with older clients.

Immediately after the release of HL2DM last night, users who run Source Engine games (including Half-Life 2 and Counter-Strike: Source) under DirectX 7 or who run with less than the recommended amount of RAM were affected by a game crash. This caused them to be unable to run HL2 or CS:S for a short time. Shortly after midnight PST, we released a fix which cleared the problem up.

And the second removed the ablilty of clients to kick other clients, I'm assuming from HL2DM servers.