Visitors to the Amazon Kindle eBook page received a nice surprise the other day: the retailing giant unveiled a limited-time Amazon Sunshine promotion, where publishers designated some backlist titles for sale at .99, $1.99 and $2.99. Will variable pricing come down the road?

Your perception of more Kindles and Nooks on subways and planes and coffeehouses is not wrong: research-firm eMarketer says the U.S. installed base of reading devices has more than quadrupled since 2009, with 20 million eReaders in consumer hands by the end of this year.

It's an important milestone, even if the details are somewhat vague: Amazon says it now sells more eBooks than print books -- hardcover and paperback combined -- though revenue figures were conspicuously missing from the mix.

The New York Times will grant eBooks a new level of legitimacy, announcing that a listing of eBook best-sellers will be added to the company's closely watched listings of book best-sellers.

Amazon is raising the revenue rate it pays to newspaper and magazine publishers to 70 percent -- the same rate now paid to most eBook publishers -- as long as they allow readers to access content on all Kindle devices and applications, even those on non-Amazon devices.