Given DigiTimes' spotty record when it comes to pushing rumors you might be inclined to read "Digitimes Research" as a kind of oxymoron. Unfortunately, as long as Amazon refuses to publish specifics with regard to units sold, these analyst estimates are as good as it gets. What's interesting is that DigiTimes' checks at upstream suppliers reveal that Barnes & Noble's Nook accounted for 53 percent of all e-book readers shipped to US vendors in March. Interesting since Kindle is Amazon's bestselling product and an increasing share of the company's revenue is based on sales of electronics and general merchandise. Still, it's our guess that Amazon doesn't care too much about selling its own hardware (it's in the business of selling other people's content and goods). Besides, the Kindle app is already available on a wide range of devices including Apple's iPad and a wide variety of smartphones. One place you can't install it, however, is on the steadily improving Nook.