A newly discovered patent filing from Microsoft could potentially turn your Kinect camera into a remote monitoring device that would allow for the regulation of license-restricted content (via Eurogamer). According to patent application #20120278904, "the users consuming [individually licensed] content on a display device are monitored so that if the number of user-views licensed is exceeded, remedial action may be taken."
In simpler terms, if you pay for, say, a movie rental on Xbox Live that is technically limited to your eyes only, this monitoring system could use a TV-connected camera, such as your Kinect, to see if anyone else is watching with you. Big brother might not be watching, but Microsoft certainly could be at some future date.
Now just because a patent application is filed, that doesn't mean it will be approved. Similarly, an approved patent may ultimately go no further than the R&D stage. This news doesn't automatically translate to "OMG MY XBOX IS WATCHING ME," but it's definitely something that should be of interest to folks who prefer to maintain their privacy. At last count, that amounts to roughly everyone.