Microsoft has something Apple and Google must envy. It has sold 67 million Xbox 360 video game consoles and has more than 40 million Xbox Live members. According to Frank Shaw, Microsoft's vice president for corporate communications, video consumption has grown by 140% each year on the Xbox since 2008.Apple and Google have the name as innovators, but, clearly, Microsoft still knows how to play the game. Xbox did not emerge as a full-fledged streaming service by accident. And you cannot blame happenstance for what's about to happen: The combination of Windows 8 and Xbox will connect your mobile devices -- smartphones and tablets -- to not only your PC, but, maybe more importantly, your television screen. Relative to Xbox, Apple TV and Google TV are abject failures. There's an obvious reason: Gaming leads the way on Xbox. You fire up your Xbox to play Tiger Woods PGA Tour and you realize, whoa, this thing does everything any other streamer can do and more. When you stop and think about it, it's really the most brilliant innovation that investors, swept up by Apple euphoria, largely ignore. Well-positioned to win the battle for the living room -- or at least continue to establish itself as the leader -- it will be interesting to see what Microsoft does from a mobile standpoint. While most talk has centered on smartphones, particularly the firepower Microsoft and AT&T ( T) have put behind Nokia's ( NOK) Lumia, the tablet space might end up an equally as interesting battleground.