Amazon announced yesterday that sales of Kindle books outnumbered sales of hardcover books over the last three months.
In that time, Amazon said, it sold 143 Kindle books for every 100 hardcover books, including hardcovers for which there is no Kindle edition. The pace of change is quickening, too, Amazon said. In the last four weeks sales rose to 180 digital books for every 100 hardcover copies. Amazon has 630,000 Kindle books, a small fraction of the millions of books sold on the site.