Apple knows that many developers pay to have fake positive reviews written about their apps. The advantage of having positive reviews is that more people will likely download the app and it has an influence on search algorithms on the App Store. Having a five-star review is considered suspicious.
Apple has now been removing fake reviews from the App Store. Developers often post fake review jobs on freelancer marketplaces or they buy them in bulk from third parties. Below is an interesting tweet that Ouriel Ohayon sent out:
The app, “Better Fonts Free?” had all of its June ratings disappear overnight. The app had around 20,000 ratings.
This is not the first time that Apple removed ratings from an app. It is unknown how Apple spots fraudulent behavior.