Thanks Derrek! The App Store is definitely a great way to make money, though it's of course up to developers to execute and position themselves well.

For us, the only issue is communication- we've now had a Kindle companion application, Kindling, in review for 94 days, without any communication outside of form responses from Apple.

We take the long view- the App Store is currently the best mobile platform, but we're working on expanding our business to other platforms. I think it's pretty crazy for any developer to be focused on one platform exclusively, and have 100% of their revenue capable of being destroyed with a single click of the 'Remove from Sale' button in Cupertino.