Not just Sony.
Many, many years back, before the Anonyputzs had even graduated from Firewalls 101, I had a friend that "ran" a four-page website for her clan. One day she called me, completely bewildered, because someone had defaced her site. Security wasn't brilliant, but she'd never assumed that someone would actually want to attack a website which didn't even hold credit card details. A lot of gamers groups and sites grew up with the same idea, Sony amongst them by the look of it, and you have to wonder how many of the other big boys, like Steam, are actually relying on old code that may not be that secure. Steam is a worry as users often not only buy stuff, meaning Steam has their credit card details, but it also holds copious details on users systems, addresses, and gaming preferences. And it has a distribution system with hooks into the OS that could allow a hacker to install a botnet overnight to a massive number of powerful PCs, PCs with guaranteed broadband connections and probably limited security - a DDOSer's wetdream.
I bet Sony are now doing the long-overdue security review, and are realising they have a lot of tightening up and probably re-coding to get to the point where they can go back to business with a solution fit for the current level of capable if mindless vandalism as espoused by the Anonyputzs. I only hope companies like Steam and Blizzard are doing the same.