This is what digital books from Penguin—one the mega-publishers—will be like on the iPad. Children's books that are games, interactive anatomy books, and an augmented reality intergalactic GPS system. This is the future we've been waiting to see.

The excitement over the iPad? It's this precisely kind of stuff that people are wetting themselves over, little slices of our tablet dreams. What is a book anymore, in this format?

The ePub format that'll be the vessel of choice for ebooks sold in the iBooks store is designed to translate traditional books to a digital format. Which is why, Penguin Books CEO John Makinson says that "for the time being at least we'll be creating a lot of our digital content as applications for sales in app stores in HTML, rather than as ebooks. The definition of a book itself, as you can see, is up for grabs."

It's been expected that the preferred form of newspapers and magazines on the iPad will be apps, given their dynamic content—both in terms of being constantly refreshed, and their desire for video and interactive elements—that's not particularly suited to the ePub format being sold through iBooks. But Penguin's decision to pursue books as applications possibly foreshadows a really interesting split for book publishers as well: Sell a book or sell an app? Which could have some interesting implications for Amazon and their contracts with book publishers as well.

Somehow, things just managed to get even more complicated. But Penguin thinking beyond the book is exciting enough that I don't really care. [PaidContent]