The future of radio is going to be very, very measured.

Emmy Advanced Media: Do You Really Want To Know?:

"The lingua franca of the television media business is Nielsen Ratings, but if the box is opened, that will immediately change. Good, bad, or indifferent, a common currency and common unit sizes make intelligent negotiations possible. How will the world of media look when every buy has a census-based, quantitative measurement attached to it?"

The above quote references television, obviously.

But clearly, radio will follow. Precise measurement is getting closer, not farther away. And it serves to figure that in less than a decade, Arbitron isn't going to be working off of a bunch of pitiful telesurveys.

There will be culture shock and rebellion when this first happens, and after that, radio (if it's even recognizable as a form of mass media) will recover.