If Nielsen ratings are used to determine advertising costs, why give a flying poop about anyone who is too poor to afford even basic cable?
There should be a whole level of ratings based on anonymized reporting of user-initiated Tivo recordings, so they know what people with some money are waiting to watch -- even if they're skipping the advertisements. Maybe ESPECIALLY if they're skipping them, encouraging alternate advertising methods like product placement.
I remember reading a couple years ago about a company in Santa Monica which was recording P2P metrics and selling the reports to Hollywood studios. The number of seeders, time-to-distribution, length of time a torrent stayed active, etc. all that is useful in determining popularity.