How Much is the Kindle Worth to Amazon? Maybe $5.42 Billion in 2011

We don’t know much about the Kindle ebook reader, Kindle apps, and ebook sales in terms of sales. Amazon doesn’t say how many Kindle devices have been sold. They hav noted that ebooks outsold paper books during the last holiday season. And, it is fair to say that you can find a lot of people reading Kindle ebooks on the Kindle reader itself or using one of the Kindle apps ported to a wide variety of desktop and mobile platforms.