The Next Web reports that a recent update to the Kindle app for iOS is able to skirt around one of the App Store's long standing restrictions, namely that any content discovered and purchased via an iOS app is subject to Apple's 30% take.
That restriction is why the current Kindle for iOS app redirects users to Amazon's website to purchase books rather than integrating it into the iOS app itself.
While Apple hasn't eased up on its restriction, the new Kindle app offers a roundabout way for Amazon to sell books without having to hand over 30% of the proceeds to Apple. The new Kindle app offers a new feature which enables users to search for books from within the app and then download a free sample for viewing. Once a user has completed the sample, they are then presented with an option to email an online link to the book they've just finished sampling.
Yes, it's convoluted, but it also offers a significantly improved user experience for those 'just looking for a book'. It lets them grab the book quickly for free and, once they're locked in, offers them a way to purchase it from a link. I believe, just breezing over the guidelines again, that it also does not violate the rules of the App Store as they stand. We've reached out to Apple to clarify.
I agree that it is a bit convoluted, and at the risk of jinxing the feature, I don't think Apple will have a problem with it. I downloaded the update and noticed that when the email link is pressed, it doesn't automatically send an email to my Amazon user email account. Rather, it sets up a message originating from my default email account in iOS, leaving me to fill in the recipient field. I was, however, able to have books automatically added to my Amazon wishlist.