It's also possible that the Kindle -- while attracting lots of media attention -- is such a small part of Amazon's overall business that the company doesn't feel the need to disclose how many it sells, suggested Harry Wang, director of mobile research with Parks Associates.
"Kindle is a small portion of the revenues earned by Amazon, and the company has no obligation to disclose non-material financial information," Wang told the E-Commerce Times. "It doesn't mean the Kindle isn't selling well; it's just Amazon's practice."
Amazon had sold a total of nearly 3 million Kindles by the end of 2009, Wang said, citing his own market analysis.
"The latest version -- being priced much lower than previous ones -- should show a faster uptake," Wang opined, "but the reality is the Kindle is competing with a host of new e-reader devices, as well as the iPad. So, I believe the current version is selling better than its predecessors, though not significantly better."
From the article, "Why Amazon's Cagey About Kindle Sales" by Sidney Hill