So it turns out that Amazon has patented a marketplace to sell 'used' e-books.
What does this mean? Well Lucy Mangan at the Guardian has some thoughts:
“The idea is that when you have read your “book”* (on your cold, hard, comfortless but arguably more convenient screen) and don’t wish to “keep” **(or, rather, retain access to) it, Amazon will transfer the file from your account to a buyer’s, taking – of course – a cut in the process. Thus a market is created, and authors and publishers are quite possibly cut out of it, in one fell swoop.”