The LA Times provides a bit more detail and analysis:
Authors Charlaine Harris, Stephenie Meyer, James Patterson, Nora Roberts and Stieg Larsson have each sold more than 500,000 ebooks for the Kindle, Amazon.com announced today. ...Additionally, as noted by Market Watch, Amazon.com says unit sales of its Kindle have tripled since the price cut on the hardware late last month. Amazon posts second quarter results on Thursday. They'll be strong. Count on it.
But what isn't being said is that these aren't necessarily new books; most of these authors have an impressive backlist. James Patterson has published almost 40 novels; Nora Roberts' books have been issued and reissued so frequently that it's almost impossible to tally her published work. Stieg Larsson, who died in 2004, is the underachiever: His popular mystery series consists of only three books.
When CDs began to outpace vinyl, music companies realized that they could sell the same original works to fans a second time, in a new format. How much of Amazon.com's Kindle sales are an echo of this -- readers purchasing much-loved favorites in a new format -- is impossible to say without seeing sales figures based on specific titles. And that's something that no companies, neither publishers nor Amazon.com, seems interested in releasing. ...
