"Next Monday, Amazon will likely unveil the next version of its Kindle e-book reader at a press conference in New York. But how did the gadget do last year before it sold out in November? Pretty well! Via a research note, Citi analyst Mark Mahaney now thinks Amazon sold 500,000 Kindles last year, more than his previous estimate of 380,000 (and if Amazon hadn't run out of Kindles in November, it could have potentially sold 750,000, Mahaney estimates). Mahaney now thinks Amazon's all-in Kindle revenue could reach $1.4 billion in 2010, or an impressive 4% of Amazon's revenue that year. This assumes that Amazon will sell 1 million Kindles in 2009 and 3.5 million in 2010; that Kindle owners buy one book per month, etc. It's an admittedly rough estimate, but not necessarily an unbelievable one."