Via Joshua Gans, Harry Potter fans can now get their favorite books in digital format. But not from Amazon or the iTunes bookstore. Instead, the exclusive source of Potter ebooks is J.K. Rowling's Pottermore website where you're able to get them in formats that run on all major e-readers and tablets.
This is exactly the kind of thing I had in mind when I said it was ridiculous to be worrying about book publisher collusion and price-fixing. It's just way too easy to bypass traditional distribution channels in this space for anyone to have enduring pricing power.