very nature of a book is evolving. Such as Byliner, a new hybrid of journalism and books, where we find longer-form journalism. They'll publish works online for a short while, then they'll be available as paid downloads or as books. They will split the revenues 50-50 with the authors.
Other sites are trying similar experiments in different forms of journalism/book publishing; even Amazon is getting into the act with their "Singles". I predict we'll see a lot more of these experiments, as the freedom from the tyranny of physical book lengths and physical distribution enables a great degree of experimentation at little cost.
Meanwhile, the burgeoning ebook field has its superstars, such as Amanda Hocking, who's made hundreds of thousands of dollars in a short time with her ebooks. Now she's gone and signed a four-book publishing deal for more than $2 million with St. Martin's Press. Which will get her works in a different form in front of many more readers. Print is still kicking it, seems, but it's clear that ebooks are what got Amanda Hocking her deal. Authors no longer have to wait to be discovered; they can start selling ebooks and making money right away. And if you are successful at selling ebooks, you may find a lucrative deal from a traditional publisher laid in front of you... and these days, those offers are going to have to be much better to entice you away from the 70% royalties you can earn from an ebook.