Seems that a hugely logical application for this kind of tech is for university textbooks. I would have loved to have something like this when I was a student! Have any universities started to adopt any of these formats? This would turn the new/used textbook business on its ear.
How about libraries? No more going to the B&M building to check out a book from my town library.
It also seems logical that the reader devices themselves eventually become ultra-cheap, or even free, with subscription services. This would drive the market much faster, similiar to how it drove the cellphone business to the point of ubiquity.
Maybe all of this will happen after the basic tech is ironed out, again similiar to the cellular industry.