It's perfectly fine that the messaging APIs aren't available yet.  The end users don't want the application messaging API's to become available. Ever. The OpenSocial specification states that websites (containers) don't have to implement the application messaging or invitation functions.  If MySpace is really ...

Here's an open letter asking MySpace to fight application spam: http://fight.opensocial.spam.googlepages.com/home   We don't want MySpace flooded with application spam like Facebook.