WotLK OS requirement?

Q u o t e:
Will you have to go out and buy Windows Vista or will you still be able to run it on Windows XP?

The specifics for what will be required for running the expansion have yet to be worked out but it seems unlikely that we will be moving over to have everyone only able to play if they have Vista. We try to keep the game as accessible to as many people as possible and take that into account when developing our content.