E-book readers have been around for several years already. They haven’t really taken off yet though, mainly because most of them are expensive.
It kind of changed when Amazon released its Kindle. The Kindle won’t exactly win any beauty pageants, as it looks a bit clunky and all that (Sony’s Reader line takes the cake for good-looking E-Book readers), but it still sold pretty well; so well that it’s almost always sold out. The Kindle has a buy-on-demand feature wherein the user can get new books, magazines, and other materials off of Amazon as long as the reader is near a data-enabled cellsite, and at a lower price than the paper edition at that.
The biggest stumbling block for E-Book readers like the Kindle (and E-Books in general) is the fact that nothing beats the feel of real paper for a lot of people. For now, folks still look for that feeling of turning an actual page over while reading. There’s also the smell of a freshly published book that for now, no E-Book reader can simulate.
That may still change though, and it probably will, thanks to advances in technologies such as electronic ink screens and easier book downloading.