While smartphones have cannibalized a chunk of the low-end digital camera market -- leaving enthusiasts to seek out digital SLRs and mirrorless camera systems like the Panasonic Lumix G and Sony NEX cameras -- tablets are paradoxically pushing some early adopters toward a product that does less.

Of course, many readers of digital books are indeed interested in all manner of multimedia. In addition to a wide array of tablets, the Nook Color addressed those consumers, but left the original dual-screened Nook looking a bit long in the tooth. With the new Nook, Barnes & Noble covers the key features of WiFi and a touchscreen, and continues to abstain from cellular to keep prices lower and create a nearly distraction-free reading experience. But Barnes & Noble thus gives up something in the new Nook, too -- a target platform for its budding third-party development efforts.

As today's inherent compromises between e-paper and LCDs continue to fade, we will see displays that combine the sunlight readability and long battery life of the former with the color and video support of the latter. At first, these will cost more than today's monochrome e-paper screens, but over time they will be suitable for inexpensive e-readers such as the Nook and Kindle.

As these the less versatile generation of displays fades away, so too may the idea of a product focused purely on reading. Returning to the digital camera market, advanced amateurs and pros long snubbed the video capture capabilities in point-and-shoot digital cameras in the name of a pure and undistracted experience of capturing superior still images. Visit a high-end photography conference, though, such as PhotoPlus Expo in New York, and you'll see that many pros embracing video capture, and that their assignments are increasingly requiring it.

Just as these extra features have not made for worse images, do-it-all e-readers haven't -- and won't -- mean the end of a pure reading experience. Limited technology, though, may no longer help one focus. Just as for the passionate pro photographer who must now decide when to capture a still versus video, the exercise of electronic book reading will require the exercise of self-discipline.