Valve has announced that parts of Steam will be down on Thursday due to a maintenance update.

Beginning at 6pm Pacific time Thursday February 4th, we will be performing software maintenance on some Steam servers. Some Steam services will be offline during this time. Affected services will include the Steam Community, in-game matchmaking or lobbies, downloading games from Steam content servers, and making purchases from the Steam store.”

Players will still be able to play games though, which is what matter the most, anyway.