That might have been true before Tivo but not anymore. Tivo (and others with appropriate technology) track viewer habits and markets the data (tremendously valuable because they - and Visa, MC, AMex et al, know exactly who you are when they pulled your credit when you signed up) so keep that in mind when you start getting direct mail solicitations trying to sell you the latest installment of Naked Bimbo Girls Gone Wild....
Hmm...didn't know that. I don't have Tivo, so no one is keeping tabs on me. Actually, I don't have any TV connection, so I KNOW nobody is watching what I watch.
The only time I see TV is in hotels.