Device Stage is a very idealistic concept which aims to simplify the way people interact with devices in Windows 7. Microsoft’s idea is to have one place for managing all your external devices and interacting with them. Unfortunaly hardware manufacturers need to develop drivers which actually take advantage of this feature. And so far, not many of them have done this.
This article explains what this feature is, how it works and how you can use it for the devices that actually work with it.