A few months back I posted about the Sony Reader, a portable ebook device not based on an LCD display, but using eInk's revolutionary electronic ink displays that appear much like the surface of a book.
There are two advantages to the eInk displays:
1) They look like paper. The contrast is not as white as paper.. think of the background as a bright gray. The display is based on balls/spheres containing both white and black ink. A charge is applied causing the black pigment chips within a sphere to push towards the user (and appear as a "pixel") or away (resulting in the white pigment chips being visible and "hiding" the pixel as the paper color). Hence eInk displays are actually opaque and ink-based just as paper.
Both paper books and eInk displays are of course easy to read and have little eye strain, unlike LCD products with active lighting behind them. paper also offers bright contrast and readability in direct sunlight as well as by very little indirect lighting such as on a plane.
2) These displays do not require power once they are changed. In other words, if you "turn the page" on your Sony Reader and then power it off, the display still has the text in full view. Battery life is incredible, then, as no juice is needed to constantly refresh an active display such as those found on PDAs.
Well, with that being said, Mike Cane is an avid reader and blogger and has some nice things to say about his experiences with the reader: