Wait a sec, something is wrong here. I suspect the title is misleading. RockYou has maybe a couple thousand developers tops using their services. They might have 32 million Facebook customers, but those don't have passwords. They're Facebook app users.

Facebook does not permit developers to store private info without special permissions, which I've never seen apps of their ilk ask for. So while this hacker could maybe see what digital birthday card was sent to whom, that's probably about the extent of the damage.