Some hacker was able to edit moderator posts on the official www.worldofwarcraft.com forums (hence why they are down right now). Caused all kinds of havoc.
Thing is... If their forums share resources with their servers, etc., it may be REALLY scary that it would be this vulnerable. At least in my mind.
By the time it went down it still was uncertain if normal individuals were at risk as well as the moderators. It was also still unclear whether the hacker was able to see any account data or just edit moderator posts. The fact that they could only edit posts led many to hypothesize that they indeed did not have access to any specific account information, but simply gained moderator level access somehow.
I'll be watching the outcome closely none-the-less, because going into WoW I'm already deeply concerned about the inherent hack issues other Blizzard titles have had, i.e. Diablo2.