It supports Xbox 360, Windows 8 and Windows Phone. It allows other devices to synch and display context-sensitive information. All Microsoft games will support it from now on.
Obviously Microsoft would love for third-party groups to jump on the wagon and get to making some smart SmartGlass apps, or "activities" as they refer to it in marketing speak.
Anyone part of the Microsoft Game Developers Network now has access to the SDK for SmartGlass. Time will tell if this screen swapping/moving/synching doohickey is of any use to anyone.
"Xbox SmartGlass is a free application for Windows Phones, Windows 8 and other portable devices. By delivering companion content and control to enhance your experiences on the Xbox console, Xbox SmartGlass makes enjoying TV, movies and music, web surfing, and playing games even better," blurb Microsoft.
"Imagine that your tablet or phone knew what you were watching on TV and presented bonus features without you having to lift a finger. Xbox SmartGlass turns any TV into the ultimate smart TV."