Boards
Say you buy a book second hand.
And then you realise it would be easier to read on your Kindle so you source an illegal ebook version via torrents or whatever and you read that version.
Then you delete the ebook version and give the book away or whatever: we'll assume you have no time to re-read the book because you're a voracious reader and "books you've not read >> re-reading books you've read".
Morally questionable, right?
Hmmm, interesting...