Kindle iPhone app: Not crippled, just saving money

John Gruber linked to the Ed Burnette ZDNet article wondering if Amazon intentionally crippled the Kindle iPhone app.

In particular, he wonders why Amazon makes you order books from their web store instead of through the iPhone app:

Take shopping for a new book, for example. When you try that from the iPhone reader, the software simply opens up the web browser on the Kindle store at amazon.com. It’s practically impossible to actually order something from there, because the site is not very friendly to the small screen. The real Kindle has a real store that you can use right from the device. Obviously Amazon would rather you do your purchases from there.

My guess is that Amazon wants to avoid giving Apple the 30% commission on sales through the app store, which I’m guessing that Apple would insist on, if Amazon were to build a book buying UI into the iPhone app.