At present, this iBook format will only work with Apple’s iOS devices, and will not work on other devices. Even so, Apple has restricted sales of any iBook formatted documents coming from iBooks Author to the App Store. VenomousPorridge comes out against these terms suggesting that trying to control the output format is overreaching and falls apart in certain cases:
“Or how about this: for a moment I’ll stipulate that Apple’s EULA is valid and I’ve agreed to it implicitly by using the software. Now suppose I create an iBook and give it to someone else who has never downloaded iBooks Author and is not party to the EULA, and that person sells it on their own website. What happens now?”
As John Gruber points out, beyond the 30% App Store cut, Apple may simply not want to feed content to competing bookstores such as Amazon or Google.
“Second, it’s about not wanting iBooks Author to serve as an authoring tool for competing bookstores like Amazon’s or Google’s. The output of iBooks Author is, as far as I can tell, HTML5 — pretty much ePub 3 with whatever nonstandard liberties Apple saw fit to take in order to achieve the results they wanted.”
As we’ve mentioned, as a new format, the iBook format isn’t even compatible with any other devices, but it’s easy to imagine that compatibility could be implemented by Google or Amazon if the format takes off. Apple achieved a similar lock-in advantage with their own App Store apps, though those apps can’t run on competitors’ devices due to technical issue rather than licensing ones.