A display technology that aims to provide the appearance of traditional ink and paper. Unlike flatscreen displays that rely on emitted light from a backlight, electronic paper is designed to consume relatively little power, and uses ambient light (or front/edge lighting for use in the dark) that is either absorbed or reflected back to the viewer, just as with ordinary paper. This means that, unlike most displays, electronic paper works well in strong sunlight. The display is also bistable, meaning that any text or image being displayed will remain when the power is switched off. Initially, the range of applications of electronic paper was limited by its relatively low refresh rates, but the lack of a backlight is a significant design advantage, opening up the possibility of very thin and flexible displays. See also electronic ink.

http://thefutureofthings.com/3081-the-future-of-electronic-paper/ Interesting article on the history and future of e-paper