"ComScore released a study of online sales of "In Rainbows," a new record album from the band Radiohead. During the first 29 days of October, 1.2 million people worldwide visited the "In Rainbows" site, with a significant percentage of visitors ultimately downloading the album. The study showed that 38 percent of global downloaders of the album willingly paid to do so, with the remaining 62 percent choosing to pay nothing."
-- From the press release that has more numbers about what users paid how much on average. ComScore blog defends Radiohead's business model: "for every $1 in sales coming from album downloads, sales of their [$80] Discbox generated $2."
The point of the story: the audio tracks do not have to be the merchandise, but they are a great way to advertise something else, something that is a scarce commodity and can't be freely downloaded and multiplied.
Financial Times wrote as much last month: "Radiohead's much-debated decision to let fans choose what they pay for its new album online is a promotional tactic to boost sales of compact discs, the band's management said yesterday."
Update [Nov 11, 2007] Radiohead denies comScore's numbers (MTV via PSFK).