I didn't find the post to be very useful, but this part is worth the read:<p>><i>I believe (conjecture, yes) that the figure we are missing is Books-Per-Person.</i><p>>If you have a Kindle, as I do, how many books did you buy in the first week or two? How many unread books do you have on your Kindle? Unlike with print books, you don’t have to look at a stack of unread material like undone homework. Ergo, you purchase more digital books than you would ever purchase in print. If Amazon is selling 180 Kindle books for every 100 print books, I wouldn’t be surprised if 10-20 people are responsible for the former, whereas 80-100 people are responsible for the latter. This reflects that Kindle owners are buying more books per capita, not that paper purchasers are buying fewer.