We lightly touched on the three screens dream of Microsoft back at the Worldwide Partner Conference in Los Angeles earlier this year. CEO Steve Ballmer wrapped up his speech with a slide that showed the tight integration between products, seen above. For a good example of the "three screens" vision, check out the RC-AirSim demo.
Tim Carmody at Wired has published a superb write up of the integration we are starting to witness between Microsoft's product line. He spoke about the Xbox Companion app for Windows Phone that Microsoft’s Derek Snyder demonstrated. Derek created a scenario where you are watching an animated film on the Xbox but can't put a name to one of the voice-actors. The first call would be to get out a smartphone and search on Google or IMDB. With the Xbox Companion app, you can see all the relavant information about that film you're watching right in your hands.
"What’s more, it doesn’t just do this over Wi-Fi, if the Xbox and WinPhone are on the same local network. It can do it completely through the cloud, using the common Windows Live ID on both devices. If the Xbox had 3G/4G cellular data like the Windows Phone does, you wouldn’t even need a local router."