How well is Amazon's Kindle electronic book reader really doing? Well, according to Citigroup's Mark Mahaney, whose analytical prowess enables him to extrapolate sales figures from little more than Kindle's sales ranking on Amazon's Web site and from the number of customer reviews it has received, the Kindle is doing quite well. But according McAdams Wright Ragen analyst Tim Bueneman, who's actually, you know, spoken with some Amazon officials, it might not be selling as well as Mahaney claims.