So whats actually the deal with this "official" Facebook app FROM MICROSOFT? Hows that it's the only official Fb app for Windows and its not made by Facebook?
The answer to that is, no one knows. Google has indicated it has no desire to make apps for WP.
I wouldn't hold my breath waiting. We don't know what the magic number is but we do know it needs to be higher than the current ~3% market share that WP currently has.