The store button in the Audible app (left) and the new version acknowledging the removal of the button to comply with Apple’s rules (right).
UPDATE: [Monday, October 10, 2011 at 12:40am ET]: Well, that sure was quick. A new version of the Audible app has just gone live on the App Store, without the link to Audible’s Mobile Store from the app. The development actually means someone at Apple’s App Store team messed up. We’re still bewildered how anyone could have missed the big orange button.
If it’s not a change of heart, then it’s entirely possible Audible simply agreed to sharing 30 percent on revenues generated from sales on audible.com coming from the in-app link. You could ask yourself who in their right mind would do that, but remember that Audible has been a long-time iTunes partner providing audio books for Apple’s content store.