But 2010 will see a "huge surge in e-book sales," he predicted, citing the various kinds of devices running e-readers. In addition to its recent announcements, Fictionwise expects to add more form factors and devices. For example, Pendergrast said the company is working on an e-reader that runs on smartphones using Google Inc.'s Android operating system, and . that's the size of a sheet of paper (8.5 by 11 in.), although not quite as thin.

While the availability of more devices that can work as e-readers is expected to improve sales, Pendergrast said there is a "tipping point" of e-book popularity that will occur in 2010, as more consumers see users reading e-books on planes and subways.

Fictionwise research also shows that the company's typical customer is a woman, between 40 and 50 years old, who tends to have a higher-than-average income and level of education. In comparison, a few years ago, the typical customer was a man, who might have been a "gadget freak," Pendergrast said.

Because 55% of traditional book readers are women, the fact that more e-book customers are now women "is evidence that e-book sales have shifted away from the early-adopter stage," he said. "As the technology improves, e-books will be more and more accepted on the mass consumer level."

The growth will not just benefit Fictionwise but all e-book sellers and will come about partly because of the success of the Kindle and Sony readers. When the first Kindle appeared, Pendergrast said that people feared for Fictionwise's business, but the Kindle just spurred the popularity of all kinds of e-books, he said.