It's the press release that rocked the publishing world: Amazon just announced that Kindle and Kindle e-book sales are doing incredibly well.

"We've reached a tipping point with the new price of Kindle—the growth rate of Kindle device unit sales has tripled since we lowered the price from $259 to $189," said Jeff Bezos, Founder and CEO of "In addition, even while our hardcover sales continue to grow, the Kindle format has now overtaken the hardcover format. customers now purchase more Kindle books than hardcover books—astonishing when you consider that we've been selling hardcover books for 15 years, and Kindle books for 33 months."
Over the past three months, for every 100 hardcover books has sold, it has sold 143 Kindle books. Over the past month, for every 100 hardcover books has sold, it has sold 180 Kindle books. This is across's entire U.S. book business and includes sales of hardcover books where there is no Kindle edition. Free Kindle books are excluded and if included would make the number even higher.

The full press release is over here. I still expect the Kindle format to lose some ground as iPads, Nooks, and other e-book platforms proliferate, but Amazon's head start on e-books continues to look ridiculously smart.