There is some interesting news coming from Amazon concerning their best selling MP3 album of 2008. According to this story, you could have downloaded it for free - legally.
The latest album from Nine Inch Nails was put under a Creative Commons license which meant you could download it legally for your personal use. But it was still the best selling downloadable album on Amazon.
Pretty cool stuff. Oh and I don't really recommend downloading that album. NIN isn't really for everybody.