Yeah, I could get behind the use of Real IDs and real names contained entirely in the game (in the form of Real ID chat), but I can’t even try to start and defend what they’re doing with the forums in Cataclysm.
I feel certain a few accounts will be canceled (as I’ve seen a number of people say they’ll do), and voting with your wallet is perfectly acceptable. I want to say that I think the forums will also be a deserted wasteland and everyone will flock somewhere else, like maybe the Wowhead forums, but I don’t think for a second that will actually happen. The forums will still be populated by vast quantities of people who just don’t care about it enough to not post. However, it won’t have some of the valuable stuff that is there, and we’ll probably end up looking elsewhere for it.
As for me, I’ll probably be staying off the forums regardless. I rarely needed to post there before (and mostly in Technical Support when I did), and I don’t see much changing in Cataclysm. Unless, of course, this thing where I crash every time I log out (or get disconnected!) doesn’t have a solution by then.
TL;DR: I can’t say I’m happy with their decision, and while it doesn’t affect me because I choose to not post on the forums, it will probably affect others negatively and I understand why they’d choose to boycott it as they see fit.