David Carnoy released his novel, "Knife Music," as a free book app. Apple objected to the presence of the f-word, so he replaced it with the letter F.
That "censorship" got him some additional attention and the book went to number 7 in the book apps category ("right after the Bible," Carnoy says in an interview with himself in Publishing Perspectives).
At that stage, the book was being downloaded 1,000 times a week, which led to selling about 1000 paperbacks and more Kindle versions (priced at $3.99). Those sold about 400 a month, for a total of 30,000 (hmm 30,000 times $3.99...not bad!).
One caveat: this was in the early days of 2009, when there were far fewer books available in the Kindle format.
Now The Overlook Press is releasing it as a hardcover. But Carnoy hasn't stopped using digital means to promote the book. His new publisher is allowing him to release 150 pages of the book as a free sample on the iPhone and iPad and also on the sharing site, Scribd.
Carnoy's prognosis for book apps: "I think text-based single books as apps will slowly go away. But the app route makes sense for interactive children’s books, graphic novels, and other multimedia e-books. However, the reason I did an app again is that you can’t give away a lengthy free sample in iBooks right now or on the Kindle or Nook (unless you have a special arrangement with Amazon or Barnes & Noble). So the app was really a workaround."
And his thoughts on self-publishing: "self-publishing is about speed and control for the author. It’s all about online and going direct to consumers. The key thing you lose when you move to traditional publishing is control over pricing (and a significantly larger chunk of the royalties). It’s much easier to get people to take a chance on reading you when your book prices are low. That’s why you’re seeing success stories with some of these Kindle authors who are pricing their books at $1.99 or 99 cents. People are willing to take a look at those prices if your user reviews are good. You can do especially well if you have multiple books out (as long as people dig your stuff)."
(My books are on Kindle, too, including "Your Writing Coach," published by Nicholas Brealey.)