Blizzard's RealID thing didn't make any sense to me, but that's because I was relying on the official message to get a sense of it's purpose. It's a much more straightforward when you read the article at USAToday's Game Hunters entitled "Blizzard and Facebook's friendly social networking deal launches with 'StarCraft II'."
If I thought I could top this comment over at MetaFilter, I would do so. I can't. The RealID thing is a bad idea that won't work. If it were merely a bad idea, or merely wouldn't work, maybe there'd be something in it. Accountability is crucial - you might recall our theory on the subject - and a fixed persona makes the laws of a microculture enforceable. But the idea that this persona must bear your actual name to lend it value (for you, or for others) is ludicrous.
The worst part about the official messaging is how it conflates expanded Battle.Net functionality with RealID, so that it seems as though these things are inseparable, as though your mystically-infused "truename" is a bundle of syllables congealed with a cosmic power. They chose to commingle these things in order to realize Battle.Net as a Social Network, and to develop true cultural currency (also: regular currency) thereby.