Interesting case - look at the front page of the site and there is a license comment that suggests that the authors intend to place it in the public domain but nothing that makes an absolutely clear statement of the copyright status of the work. "License? No, there is no license. It is provided as a knowledge sharing project for anyone to use. But if you use it in an academic or research like context, we would love to be cited appropriately." My guess would be that without a clear statement about copyright that Amazon are clearly in breach here? - Cameron Neylon

I'd guess the opposite: copyright inheres automatically but that license/statement seems intended to place the material in the public domain. Amazon would have been smarter, PR-wise, to license the material -- but I'm not sure the law (which as we all know is an ass) isn't on their side here. Ianal though. - Bill Hooker

Except, now it occurs to me that CCZero exists precisely because home-brew copyright statements don't work: it's harder to give up copyright than it looks. So I think I'll change my guess: Amazon would have to argue that the authors had waived copyright, and I don't think that would work. - Bill Hooker

As I said on my post - the issue with CCZero/PDDL is making sure it is absolutely watertight. A plain english statement of "you can do whatever you like" would probably be ok to rely on in most circumstances. I wouldn't want to guess whether it would hold up in court (probably depend on jurisdiction as well) but one could make a reasonable argument based on a "reasonable" intepretation of what was acceptable and that you were acting in good faith. - Cameron Neylon