I know I know, this is old news by now. 2 days is old? Well for something as big and serious as this, yeah. Diablo 3 is a new game with millions upon millions of people AT RISK. I just missed the news when it was first mentioned. But there's a good compilation of what's been going on about this over at Altos Goldish Advice.
Also, there is the IGN Daily Fix, skip to 1:10 for Blizzards word on the Hack. Still, I suggest checking out this Blue Post for what you can do to maybe sorta help protect yourself. So, sad I am adding "maybe sorta" to that based on the fact that people are reporting being hacked with Authenticators.
Anyways, with this news, I honestly feel it might not be such a great idea to jump in on the RMAH whenever they introduce it. It's bad enough that credit card information is at risk, I would not want to risk any other accounts tied to my moneys. I was thinking on passing on the RMAH anyways and wait and see how it works out.