Dave Marsh, Microsoft's Lead Program Manager for Windows (meaning he heads up the development) explains Content Protection in Windows Vista, and answers 20 of the most common questions.
It's important to emphasize that while Windows Vista has the necessary infrastructure to support commercial content scenarios, this infrastructure is designed to minimize impact on other types of content and other activities on the same PC. For example, if a user were viewing medical imagery concurrently with playback of video which required image constraint, only the commercial video would be constrained -- not the medical image or other things on the user's desktop. Similarly, if someone was listening to commercial audio content while viewing medical imagery, none of the video protection mechanisms would be activated and the displayed images would again be unaffected.
Contrary to claims made in the paper, the content protection mechanisms do not make Windows Vista PCs less reliable than they would be otherwise -- if anything they will have the opposite effect, for example because they will lead to better driver quality control.
The paper implies that Microsoft decides which protections should be active at any given time. This is not the case. The content protection infrastructure in Windows Vista provides a range of à la carte options that allows applications playing back protected content to properly enable the protections required by the policies established for such content by the content owner or service provider. In this way, the PC functions the same as any other consumer electronics device.
It's a very important read, especially if you're planning on buying a Media Center PC with the new Digital Cable Tuners from ATI.