I know there are a lot of weird things in legal documents that aren’t actually enforceable. It’s one of the reasons every contract has a part that says invalidation of one part of this contract doesn’t invalidate the whole contract. But this one makes 0 sense to me for eBooks:
“You may not:copy or burn the book or extract to a device whose principal function is to act as a storage device, for example, a CD/DVD or USB stick;”
That can’t possibly be an enforceable part of the contract. For one, if you buy the eBook from Pottermore you only have 8 downloads (per book) before you have to buy it again. Given how often hard drives fail and Ereaders/books are stolen, it seems pretty dumb to forbid users to be able to back up their books. Also, they reserve the right to terminate your account if you’re inactive for 6 months. So, forget about waiting for a hard drive crash, if you’re not a Harry Potter fanboy you can wind up only getting one download. Finally, this is in direct contradiction with the way people may choose to use their computers. Maybe I want my eBooks to be portable to read on any computer. So I would put them on a USB stick and read them whenever I want.
In the midst of otherwise pretty sane terms and conditions (and, as far as I can tell DRM-free ebooks and audiobooks), it’s a really weird term to have.