While other digital media like CDs, DVDs, and MP3 songs showed sharp growth rates from inception, eBooks have puttered around as a tiny fraction of overall book sales for more than a decade. In several periods, sales actually declined from year to year as publishers wavered in their commitment and interest.

The most well-known dedicated reading devices, the Kindle and Sony Corp.’s Reader, try to emulate the look of the printed page with a display technology known as “electronic ink.”

Many find the result pleasant to read, but e-ink also imposes significant limitations on the devices. They can’t be backlit like other screens. They can’t show color. They’re also slow to update, making them difficult to use for web browsing or other computer activities.

The Kindle has a wireless connection directly to Amazon’s store, meaning users can buy and download books to the device within minutes. Until now, Sony’s Reader has lacked a wireless capability and thus needed to be connected to a computer to load books. But that’s about to change: Sony plans to offer an eBook reader with the ability to wirelessly download books like the Kindle, injecting more competition in the crowded eBook reader market.

Sony’s $399 Reader Daily Edition will go on sale by December, Sony executives said last month at an event at the New York Public Library. The device has a 7-inch touch screen and will be able to get books, daily newspapers, and other reading material over AT&T Inc.’s cellular network.

Sony has sold eBook reading devices with e-ink displays in the United States since 2006, but has seen most of the attention stolen by Amazon, which launched the Kindle with similar e-ink technology a year later. The latest version of the Kindle–which is not controlled by touching the screen–costs $299 and uses Sprint Nextel Corp.’s wireless network for downloads.

Sony also has begun selling a “Pocket Edition” eBook reader with a 5-inch screen, for $199, and a larger $299 touch-screen model. Neither has wireless capability, so both have to be connected to a computer to acquire books.

Though Sony is following in Amazon’s footsteps by adding wireless capability, its eBook strategy differs in crucial respects.

The only copy-protected books the Kindle can display are from Amazon’s store, and the only devices the store supports are the Kindle, the iPhone and the iPod Touch. Sony, on the other hand, has committed to an open eBook standard, meaning its Readers can show copy-protected books from a variety of stores, and the books can be moved to and read on a variety of devices, including cell phones.

Sony also has announced that its Readers will be able to load eBooks “loaned” from local libraries. A library card will provide access to free books that expire after 21 days.

The library connection “would seem to be something Amazon would never embrace, so that could be a key differentiator,” said Richard Doherty, director of research firm The Envisioneering Group. The feature also could prove popular at colleges and universities.

Campus IT chiefs who spoke with eCampus News said the expanding number of eBook options eventually will bring down the cost of eBooks and the devices used to read them–ultimately making such devices commonplace at colleges and universities.

Susan Metros, associate vice provost of technology-enhanced learning and deputy chief information officer at the University of Southern California, said eBook sales will boom when companies like Sony and Amazon are able to combine the mobility of the iPhone with the screen size of a laptop computer–perhaps as a device students can fold and carry when they’re not using it.

“The whole idea is taking the inherent capabilities of technology and adding features that you just can’t get from the paper book,” said Metros, a chairwoman for EDUCAUSE’s learning initiative advisory board. “We’re waiting for that device with the perfect footprint.”

A major shift will come, Metros said, when eBook companies unveil devices that incorporate illustrations, color, and embedded video, rather than just black-and-white text.

“If you’re looking to really re-establish the textbook market, I think that’s how it’s going to change,” she said. “There should be a big visual component there.”

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