Thus my quotes around "bought" . Again whilst technical people likely know the consequences of buying DRM protected content, I think that a non-technical person who suddenly found their paid for content removed from them due to an automated process locking/deleting their account would be quite upset.
People are, for better or worse, entrusting more and more of their content to cloud services, things like photographs, documents they've created, music etc etc.
> You're just renting them.
It's not renting really. If I rent a physical book (or house, etc), I have exclusive access to it. Nobody else can possess it. It's for this privilege that I'm paying. Obviously, this is not true of ebooks because 'X' persons can "rent" at the same time.
You're just licensing them. You're just paying for a license which can be revoked at Amazon's whim.
I'd look up some of the free tools out there and backup/un-DRM your Amazon/Nook/Google e-books. There are some guides out there for extracting your books notes as well.