There has been a lot in the news lately about the Kindle -- the Amazon/Macmillan pricing fight, Amazon offering a new 70/30 percent revenue split, Amazon's new SDK, and of course the competition represented by the Apple iPad.
Lost in all this news was an announcement regarding the number of Kindles sold. On Jan 28th, Amazon released an earnings report, and Jeff Bezos announced, "Millions of people now own Kindles." Several sources have stated that the actual number is 3 million Kindles. (Contrast this with the estimate that the iPad will sell 4 to 5 million this year.)
Sources:
techcrunch
Washington Post
Business Insider