From Seeking Alpha:
Amazon‘s shares rose 4% on February 13, after an analyst note fueled further optimism about the company’s Kindle e-book business. Amazon’s Chief Executive Jeff Bezos noted in the fourth-quarter 2012 earnings results that e-books are a multi-billion category for Amazon and grew at approximately 70% y-o-y in 2012. In contrast, the physical book sales registered their lowest December growth in 17 years at about 5%.
. . . .
Morgan Stanley’s Scott Devitt estimates that the e-book market is a lot bigger than previously thought and that owners of Kindle e-readers and tablets are reading more e-books. . . . He estimates worldwide e-book unit sales to have reached 859 million in 2012, up considerably from a previous estimate of 567 million. Leading research firm Forrester Research estimates that the U.S. e-book market will reach $13.6 billion by 2017.
Link to the rest at Seeking Alpha