I'm wondering what Amazon uses to identify ebooks. I strip the DRM from all my books before putting them on the Kindle, so I have no DRMed ebooks on there. Also, I have deDRMed books from my previous Amazon account, which Amazon cancelled when it was hacked last year
. I can highlight and post a passage from one of these deDRMed books I bought from Amazon but is not on my current account and still have Amazon find it and list the quote as from the correct book. However, other titles downloaded elsewhere only get "from a personal document" listed. Does anyone know what Amazon uses to identify their books? It's not the title and author metadata and it's nothing in the DRM (since I strip that). I think it would be cool if there were a way to put that information into ebook files I make with Calibre or something so Amazon will recognize them.