The Steam forums are closed for the moment, but the program itself is running. Users saw a new category in the forum directed them to open a site named “Fkn0wned” Many users also complained that their email ids related to Steam accounts were “spammed with ads for the web site” The forums are not working as Valve conducting the investigation and recovers from the attack. When forums are back will require that all users change their passwords as well as those who used the same password for forums on other sites also change.
Source: https://thehackernews.com/2011/11/possible-credit-card-theft-in-steam.html