Amazon: We sell more books in Kindle format than hardcover.

Amazon today released an announcement boasting that sales of the Kindle device have tripled since the unit price dropped from $259 to $189. And with that, a related piece of news. Founder Jeff Bezos: "While our hardcover sales continue to grow, the Kindle format has now overtaken the hardcover format. Amazon.com 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."