Here is the story, but no this model won’t much change the music industry. Yes you really can download this album and "tip" Radiohead as you feel inclined to. But note that:
1. Radiohead is an indie cult band with extreme loyalties from its partisans and the possibility of attracting more such partisans by seeming "cool."
2. Radiohead peaks high on the charts (#3 for their last release, if I recall…) but I believe they sell the product pretty quickly and don’t have a long run at the top. Again, they’d like to widen their fan base.
3. Radiohead’s gambit has reaped enormous publicity, but this won’t be the case next time.
4. Many donors will give to a highly visible "cause of the month" (remember the outpouring of support for the tsunami victims?) but they won’t necessarily give on a regular basis.
5. Radiohead probably has an especially high ratio of touring to CD and iTunes income; see #1. This scheme is a natural for them but not for Kelly Clarkson.