Amazon recently bought Comixology, a digital comic-book platform. Comixology has (had?) a popular iOS iPad app that allowed readers to purchase new comics directly from their iPad. Unsurprisingly, less than a month after purchasing Comixology the iOS app has been updated to remove the in-app purchasing feature, in line with Amazon's iOS Kindle app.

What do you think John Gruber thought about this?

A petulant reaction, but not a surprising one.

Why did Amazon do this? Because Apple takes 30% of the price of all in-app purchases. The 30% figure is a high one, but Apple is entitled to make rules as it pleases on its own platform - to best benefit their business - and clearly for app developers it is worth sacrificing 30% of their revenue in order to access the huge iOS market. I'm sure that is how Gruber would defend the 30% rule, and I would agree with him. Amazon, however, are equally entitled to do what they believe will best benefit their business, and clearly they did not want to share revenue with one of their rivals.

When Apple kicked Google's Maps and Youtube apps out of the default iOS app collection, Gruber applauded Apple protecting its business. Amazon here is only doing the same. The net result of both decisions? Diminished experience for the user.