[M]ake a distinction between “formats” and “forms.” A hardback, a paperback, an audiobook, and many an ebook simply represent different forms of the same work. New formats, on the other hand, represent deeper changes in how authors develop content and readers consume it. The graphic novel is a recent format innovation in the West (albeit one with deep antecedents), as are the cell phone novels that have become popular in Japan.
via Tim O’Reilly, What lies ahead: Publishing – O’Reilly Radar.