Here's why futurists look to Japan: while we just got around to finding someone willing to write a book on a cell phone, in Japan people have been reading books on cell phones for years.
Keitai shousetsu (literally, "mobile novels") have been big business in Japan, to the point where two smaller publishers who only sell to the mobile market have outsold traditional, dead-tree publishers.
Given that e-books of any stripe haven't fared too well over the years and that cell-phone screens are only moderately better for text than those on the MiniDisc-based MD Books Sony was flogging in the early 1990s, you might wonder how this is possible. I think it's a number of factors:
1) An awful lot of commuters, and awfully little elbow room. Tokyo's subways system alone carries about 10 million every day, and subway cars are often crammed beyond capacity. A cell phone is a lot easier to deal with than a newspaper or a manga volume.
2) Keitai shousetsu are dirt cheap, costing only a few hundred yen (less than $15) -- which makes sense, given the lack of printing, storage and shipping costs.
3) No DRM.
4) Japan's major publishing houses got into keitai shousetsu in a big way, which I'm sure helped give the form an air of respectability.
So let's put this another way: Mobile novels meet consumer needs, are cheap and convenient, and the old guard have enthusiastically embraced the form. Translation: massive popularity and respectable amounts of money (the two publishers I mentioned earlier sold more than three million novels in the first half of this year) in fairly short order. Nope, never saw that coming.