As many of you know, due to the overwhelming success of the Age of Empires III sale, we temporarily ran out of keys to unlock the game. We have added more keys which will be automatically assigned to you, there is no need to call support or take any other action from your end. The next time you click 'View Game Keys' for the game you should be assigned one.
Cheers!
http://forums.gamesforwindows.com/t/15707.aspx

Have fun yall