Kindle Singles

Amazon had a great idea, Kindle Singles (link goes to an article, oddly, there does not seem to be any Amazon page for this) (honestly I think this is a strange way to do things), which takes advantage of the fact that ebooks are freed from the traditions of length which came with the paper format.
They are even taking submissions. The "singles" will be books with a length between long articles and short books (something like 10,000 to 30,000 words), and will of course be cheaper than ordinary books.

"'Ideas and the words to deliver them should be crafted to their natural length, not to an artificial marketing length that justifies a particular price or a certain format,' said Amazon’s Russ Grandinetti. 'The costs of print production, marketing and distribution have historically driven the page-counts of book monographs up and the word-counts of magazine and newspaper articles down'."

The Ars Technica article about this comments: "Anyone who has ever read a terrible "business" or "self-help" book consisting of a single idea furiously puffed up into 200 pages of pabulum will no doubt agree with this sentiment."
Yep, no kidding. A great many books could be reduced to article length with hardly any loss.
... Aaaaaand of course, some people's immediate reaction is to use the idea the opposite way: They take their existing business book, on Sales of course, and sell each chapter as a book! Oh, come on.

----
By the way, read this Engadget post on the subject. Man. "If I sound really sarcastic about everything, everybody will think I'm so smart".