Online bookseller Amazon.com reported last week that—for the third month running—sales of individual ebooks for the company's popular Kindle device outstripped the sales of individual hardcover books for the same period.
Many Kindle users may soon stop buying books altogether and rely exclusively on the device.
Ebook sales increased from about 1.5 times hardcover sales in April to 1.8 times hardcover sales in June. The trend in ebook sales parallels a 300 percent uptick in sales of Kindle devices, whose price Amazon cut last month from $259 to $189, achieving what Amazon CEO Jeff Bezos has called a "tipping point."
In reporting last year's sales figures, Amazon had noted that on Christmas Day 2009, sales of ebooks exceeded that of all physical books, driven by the large number of Kindles given as gifts. So presumably, a similar phenomenon accounts for a fraction of the June bump in Kindle book sales. True also, ebook sales still account for only a small fraction of Amazon's total retail book business, most of which is in consumer and trade paperbacks.
Still, these are interesting numbers. Some analysts explain this upward trend in ebook sales by comparison to hardcovers largely in terms of price. But while it's true that the $9.99 average price of a Kindle book is typically lower than that of a hardcover, Amazon's discount pricing and free shipping mean the difference is only $2 or less, in many cases. Moreover, Amazon's pricing varies considerably, depending on where titles are on the hype and popularity curve, and on other variables. For example, the Kindle version of the bestseller Eat, Pray, Love by Elizabeth Gilbert is now fully $4 more than the trade paperback edition, released less than a month ago.
It seems, therefore, as though an actual buyer preference for the Kindle format is substantially in play. And presumably—even after new Kindle users have stocked up—their preference for buying titles in this format will become ingrained and, over time, likely exclusive. This is hugely good news, not least because this gradual revolution in book reading is not—like the MP3 revolution that preceded it—being hurried along by piracy, but is emerging as a result of a conscious, willful evolution by publishers, resellers and readers.

