Apple's facing a growing problem on its App Store platform: ranking manipulation. While a lot of the spotlight areas are curated by humans, the rankings are generally not. Instead, computer-driven algorithms determine where each app falls in the various rankings for the store and each section.
Ranking position can often mean the difference between making or losing money for a lot of developers. As a result, there are ways for developers to manipulate those rankings, ranging from the generally acceptable (asking customers to rate the app highly if they like it), to the not-so-much (hiring networks of computers to log in and download or leave ratings for an app). Some of this manipulation is essentially an open secret for developers. In fact, there are even companies devs can hire (again, some more credible than others) that will promise a certain ranking or claim to improve sales.
It's been a constant challenge for Apple to crack down on devs who are using unsavory techniques without interfering with those employing acceptable means. More than a few innocent apps have been caught in the crossfire, either by being banned from the App Store for behavior they say they didn't do, or by having their rankings hurt by changes in the algorithm. As this long GamesBeat post says, Apple's methods for determining rankings aren't clear at all, and that fact can hurt developers.
There's no easy way out of this one. Apple wants to keep its algorithm hidden, just to try to keep the rankings as objective as possible. But there will always be devs who try to crack it open, and companies ready to prey on the App Store rules to scam a few bucks from hopeful developers.
In the end, the best way to climb the rankings is to have a great and popular app. People will always try to dodge that requirement, and Apple will continue to try to stop them, with good and bad results. But for developers with talent and the knowhow to make good, noticeable apps, the hope is that the App Store will always find a way to get them seen (and bought) by consumers.