"The Steam Forums are temporarily offline for maintenance. Your patience is appreciated." That's the message you'll get if you're trying to log into the Steam forums at the moment. They've been taken down due to an apparent hack that briefly saw front page text changed to advertise a game hacks site. Eurogamer say that some Steam users have had their email addresses spammed with messages from this site
A screenshot of the Steam forums before the hack shows that the official notices section at the top of the page had been altered to promote a site called Fkn0wned. The hack is a worrying breach of Steam's usually watertight security, and is especially concerning for users whose Steam login details are the same as their Steam account username and password. Valve haven't commented on the breach yet.