Look at this rather astounding statistic from Amazon’s news conference on Wednesday introducing a larger Kindle: On Amazon.com, 35 percent of sales of books that have a Kindle edition are sold in that format. That’s up, by the way, from 13 percent in February, according to a slide put up by Amazon.com’s chief executive, Jeffrey P. Bezos.
Think of what that means. Amazon has tens of millions of customers. It sold 500,000 Kindles last year, Mark Mahaney of Citigroup estimates. So even if it has twice that many in distribution, that is a lot of e-book buying by a small number of people.