Apple is currently rejecting apps that use the Dropbox SDK to provide integration with the popular cloud storage solution. The reason for the rejections is apparently that, under a specific but not inevitable set of circumstances, someone using an app with Dropbox integration could end up on Dropbox's web site and find a way to pay Dropbox for additional storage. That would violate Apple's prohibition against using external websites to circumvent Apple's 30% cut of subscriptions. Dropbox attempted to patch the problem by removing links that would make getting to the full version of the website and finding and buying additional storage possible, but the rejections seem to have continued. Dropbox is now working to try and find a more satisfactory solution and says they'll have more information on that next week.
On the surface, Dropbox broke a rule, caused a problem for developers using their SDK, and is now correcting the mistake. It doesn't appear to have been an intentional or obvious violation, but it was eventually discovered and now Dropbox and their developers have to deal with it.
It's that latter part that highlights some of the continued frustration with Apple's App Store policies, frustrations that persist some 5 years after the introduction of the App Store. The review and rejection process is still, as often as not, impenetrable and capricious. Plenty of apps with Dropbox integration are already on the App Store, presumably using the same SDK as the apps rejected today. That they weren't rejected as well doesn't excuse Dropbox or the apps that were rejected today, but it shows that what one (or many) reviewers let in, another (or many others) may reject.
One of the rejections listed account creation for both Apple and Goog
How about if an app linked you to store.apple.com?
That's part of what causes frustration with Apple's system. Another part is things like the recent scam app plague. Apps that should have been obvious candidates for immediate rejection to any reviewer who laid eyes on them, were let onto the store to violate intellectual property rights and cheat users out of money.
One absolutely doesn't excuse the other, but people have innate senses of fairness, and for rules to be respected they need to be perceived as being far. (As the old saying goes, people don't mind paying taxes only because it's generally believe everyone pays taxes.)
We want and need real humans reviewing App Store apps, but developers need to believe those reviewers are being fair, and applying broadly consistent standards with generally predictable results.
To their credit, Apple is continually improving the App Store review process. Because the process is human, they recognize they can't always predict all of the edge cases, all of the time. They've made changes over the years, sometimes major ones like un-banning the use of cross-compilers, sometimes small ones like un-banning satirical political cartoons.
So far, however, they haven't changed the policy that affects Dropbox -- the requirement that Apple get 30% of all subscriptions, and that apps can't link to external websites where the same subscriptions can be purchased without Apple getting that cut.
Again, Dropbox knew about it, accidentally broke it, and is now working to fix it. In the meantime, Apple will catch some criticism, both for the policy, and for the way the App Store handles policies. And given the power Apple wields, that kind of ongoing discussion isn't a bad thing.