Doc says that Napster et al was "the market's correction for the failure of mainstream radio not just to adapt to the Net, but even to fulfill the missions it established for itself over the decades....Napster is radio! It's about sharing record collections the way the great radio stations of yesterdecade used to do, and today's robotic commercial radio can't remember and can no longer even begin to conceive."
I think that's a great idea, but I don't think that's what Napster was about to a large degree. If it was, than the majority of songs downloaded via Napster would not be the most popular songs played on the radio. I don't know what the numbers say about that, but from what I've heard before, they are. Napster may have been about sharing new and interesting music that we otherwise wouldn't have heard if it were designed differently. But the way it worked, you found stuff you knew of (Hot Lists allowed you to discover things, but it wasn't core to the application). And most people knew of stuff from "robotic commercial radio." Napster was about getting that stuff in a more conveneint (sometimes), more economical way.