COVER STORY: Inside the Ebook Test Kitchen

However, Coliloquy eschews the idea that reading should involve more multi-media. "We want to focus on the narrative itself, with our technology in service to the story," says Lue.

One of Coliloquy's authors, Travis Sentell, employs branching technology in his tale of good vs. evil, "Fluid," but he does so with a twist. "In all of our other books, when you make a choice, you can go back and make the other choice," says Lue. "In this book, you can't. You live with the consequences of your choices. Until you finish the book, you can't choose other paths—the multiple endings are determined by the choices you make."

Tracking Devices

Perhaps the most fertile territory for innovation in ebooks is not one that's consumer-facing: analytics. As publishers get more sophisticated with ebook technology, they're able to learn more about their customers' reading habits than ever.

Impelsys, the New York City company behind iPublishCentral, the publishing platform used to deliver ebook content by a diverse group of clients ranging from Elsevier to Harcourt to Sesame Street to HarperCollins to OUP, has been at the cutting edge of analytics. And, according to founder and CEO Sameer Shariff, the app environment is at the heart of ebook analytics. Which is why Impelsys, widely available on Apple's iOS devices, is making a big push to be on Android, which has notably gained big chunks of the mobile operating system market.

"We're innovating within the [ebook] content file itself," says Shariff. "It's like a piece of software, and you create javascripts within the file to create interactivity. You're going to see a lot more sophistication and complexity in the [ebook] files."

As publishers do more sophisticated things with their apps, Shariff figures that they will be investing in teams to analyze the data they send back.