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."