TNW is reporting that a number of apps have been denied approval by Apple because they take advantage of the incredibly useful service Dropbox. The official reason given is:
We found that your app provides access to external mechanisms for purchases or subscriptions to be used in the app, which is not in compliance with the App Store Review Guidelines.
Specifically, your app enables to user to create accounts with Dropbox and Google.
It appears this ties into Apple’s super restrictive views on allowing users to pay for non-Apple features through an application, like what caused so much drama with Kindle. In this case, a link allows users to pay to add more storage space to their Dropbox account, which Apple doesn’t get a cut of, so won’t allow it to happen.
Dropbox is aware of the issue, and released a note saying:
Apple is rejecting apps that use the Dropbox SDK because we allow users to create accounts. We’re working with Apple to come up with a solution that still provides an elegant user experience.
And has already released an updated SDK stripped of the offending code.