The Spacelab blog nails it: "So now the world listens. October 10th was Radiohead day. The end effect, possibly not even anticipated, was that there was a simultaneous listening-happening as people all over the world downloaded and listened."
Radiohead has become a verb ("did you radiohead?"). The band has not only established a new business model; it has re-established the trust between producer and consumer in the music industry. Offered for free, music suddenly holds value again. Radiohead has proven that innovation is art and that art can be innovation.