People always get scared when it's about their image... but that's not what advertising companies are interested in. The original article gets it right : what's worth a lot of money is stats about number of people watching a program, gender and age repartition, watching duration etc. Those are things that help them understand their market.
And before you start complaining about invasion of your privacy, just consider a few things : Do you have customer cards ? They can monitor all your buying habits and cross-correlate them with your age, gender, address etc.
Do you have a smart phone ? It can track your position at any moment with a few meters accuracy.
Do you have a facebook account ? "They" know your name, face, address, hobbies, who your friends and family are, what products you like and dislike,...
