E-Books Like Books: Flippable, Browsable
There are many reasons why E-book readers have not really taken off as well as anyone had hoped. Weight, and interactivity are two major ones: They are bulky, heavy items that you cannot bend slightly, as you can do with a paperback book to hold it more firmly.
More than that, you cannot look at two pages at once, and turn the page in a natural and intuative manner. At least, you never could in the past.
E-book designers have recognised that failing at least, and are working to address it. One of the first designs to pull it off at least partially successfully was a duel effort between researchers at the University of Maryland and UC Berkeley mid 2008. They developed a dual-display prototype e-reader that allows two pages to be opened and closed, simulating turning the page and other book-like behaviour.
You still cannot flip through pages naturally, but it is getting much closer. In addition, the ability to detach one half of the display, and lay it next to the other to compare different pages from the same or different E-books in the same relaxed way you would handle ordinary paper documents is certainly a big plus.
Sadly, the reader is still prototype, meaning there have not been enough halves made to see if the intent is to allow the screens to be mix and matched so you could have four or five scattered about the table and still be able to reassemble functional dual-readers without much fuss afterwards. However, that aim does seem very likely.
One big problem of course, is power. Twice the displays, and detachable units means twice the power consumption of a standard E-book. The internal gyroscopes necessary to detect flipping and page turning are constantly drawing milliwatts, so unlike traditional readers, this does not just use power on screen update. Solutions to this problem do exist, such as using the kinetic energy expanded on turning the book as a power source for the book. Like all other E-book readers currently available, the display does not need electrical power to display the last image it accessed.
Continued research is ongoing. Thin paper variants - without all the boxiness - are likely to be the way forward to take this idea from the laboratory experiment stage to the actual consumer stage.
For now however, such displays remain laboratory bound, until they feel like books but with dynamic content - and have the usability of a static paper volume combined with dynamic data, they are likely to stay a niche resource.