...Kindle books that are in the company’s words, “twice the length of a New Yorker feature or as much as a few chapters of a typical book.” Generally, Amazon characterized Kindle Singles as 10,000 to 30,000 words (roughly 30 to 90 pages).
Lots of people (including myself) have predicted that e-books will reward shorter book content. In the above-linked Constant Reader from early this year, I was focused on novellas, but the idea that Amazon wants to get into the non-fiction side of that, the pamphlet-publishing business, should really be no surprise.
And I think this is good news for books: The pamphlet is a mostly forgotten form, but 20,000 words is a really good length to do a comprehensive study of a single subject. I can't tell you how many non-fiction books I've read that felt padded because the author had to turn in something book-length. And I've read a lot of magazine articles that could use some room to breathe, too. Things like this are why Amazon is kicking everyone else's ass at the e-book game.
The one thing that's not public yet is the pricing for Kindle Singles. I imagine they'll keep the prices very low, especially since they'll be involving publishers, but authors can also go directly to Amazon with Kindle Single submissions ( email@example.com).