Edit(12/11/11): The forums are now back online.
Edit (11/11/11): Valve have released a press release that can be seen when visting the forums, in addition to this the same message is being broadcast to all steam users via the client update news system... see http://www.teamsao.com/media/kunena/attachments/375/steamhack.PNG
The official Steam forums have been down for over a day now, visiting them will jut result in getting the message "The Steam Forums are temporarily offline for maintenance. Your patience is appreciated.". But one Reddit users captured this screenshot that shows the forums where hacked before being shutdown by Valve.
In addition to the endorsement of that website, some forum members were sent an email with the same text.
PLEASE REMEMBER THAT YOUR STEAM FORUM ID AND YOUR STEAM ACCOUNT ID ARE DIFFERENT. THERE IS NO INDICATION WHAT SO EVER THAT ANYTHING BUT THE FORUMS HAVE BEEN AFFECTED. ALSO IN ADDITION TO THE TWO ACCOUNTS BEING SEPERATE YOUR STEAM ACCOUNT ID IS ALSO PROTECTED WITH STEAM GUARD BUT MAYBE IF YOU ARE USING THE SAME USERNAME AND PASSWORD FOR BOTH SERVICES IT MAY BE ADVISABLE TO CHANGE YOUR STEAM ACCOUNT PASSWORD AS A PURE PRECAUTIONARY MEASURE.
