This is an interesting little system -- unfortunately, it's probably a little too complicated for most people to use, but the functionality is intriguing. WoWHorn is an open source application that basically monitors your achievements on the Armory, and will Twitter about it when you earn a new one. To get it up and running, you'll need the application itself of course, and you'll probably also need Ruby installed if you don't have it yet (OS X has it already, I believe, and Linux may as well). I don't think you'll need to input your actual WoW password (the program should be able to look up your info with just your character name and realm), but you will have to punch in your Twitter credentials if you want it to tweet for you. Once you've got everything working (and you'll have to ignore the errors, I got quite a few), you should see a tweet pop up in your feed whenever you get new points ingame.
If you're a programmer type, you can read about the making of the app, and though, as I said, the app is probably a little too hacky for widespread use (it's not quite ready for primetime yet, and do you really want to run a separate application just to twitter about your achievements for you?), the functionality is the thing here. It would be cool for Blizzard to have the Armory interact officially with other networks on the Internet, either Twittering about your character or sending your profile out to Facebook.
Not that anything like that should distract them from future content, of course. But if they want free advertising, allowing their subscribers to more easily share and disseminate information about their characters won't hurt.