How many people actually saw the commercial?

Seth Godin offers an explanation for why Nielsen is just now getting around to rating viewership of commercials:

The answer is that the networks are a critical client of Nielsen, and the last thing in the universe they want is to rate commercials. The surprising thing is that many advertisers don’t want the ratings either. Why? Because as soon as you measure, you need to admit you failed. So you need to tell your boss you wasted a few million dollars…

The Internet has been messing with (disrupting?) traditional media since the beginning but I’ve always felt the real disruption would occur in the advertising arena. Who is listening and watching our commercial messages? What do they think about them? And how are they reacting to the messages? Answers: Lots of people. They love them. Racing to make a purchase.