The Floppyhead blog has an interesting post regarding Microsoft and digital cable tuners and CableCards. The studio-backed effort to lock up the HD video path from tuner to display may have interesting consequences for Microsoft, consequences not unlike Apple's use of Fairplay DRM to anchor music tracks to iTunes.
Basically, they [Microsoft] have a monoply of the digital cable tuner market (not including Tivo since it is not a PC-based solution). How many companies have the ability to deliver DVR software and convince vendors to supply their software? No matter what Microsoft does or how far they lag behind the market, you have to use Vista to watch cable premium content on your computer in HD. No competitor can match them on that important feature. All thanks to DRM. Not innovation or feature-sets, but content protection.