Web 2.0 is all about giving Joe User more choice, more of a voice, and more opportunities for interaction. User-created content is king, as witness the rise of such sites as YouTube. However, many MMOs are still closed systems -- you can't talk to your gTalk friends within World of Warcraft, you can't post to Twitter from Tabula Rasa, and you can't there's no Facebook integration with Everquest 2.
But who cares? Chances are you're too busy playing to care about any of those things anyway. However, as these apps mature, and people find more ways to integrate them with everything else, it probably won't be too long before new MMOs will offer connectivity with them right out of the gate. Will this be a boon or a bother? Do you wish your favorite MMO already had this integration?