Just curious, how many people who have owned Kindle for a while would actually want this?
Why would you want to pay extra for another stack of paper on your shelf that you are likely never to open?
If anything I'd rather have Amazon include sticker with a book to thick on a meta-bookshelf - I read that book.
Or perhaps they should just make an option to display virtual bookshelf on the website - "books that I've read"
