Apple's stance at least seems pretty clear cut: The App Store is for apps, the iTunes/iBooks Stores are for content. Content masquerading as an App will not be allowed in the App Store, but the content is welcome in the iTunes store.
I do think they're making a fair distinction between an app that's basically a wrapper around a movie, and an app that allows access to content (eg. http://itunes.apple.com/us/app/5by5-radio/id520847556).