Google Play Store receiving improved fraud and spam detection

Google wants to make the Play Store a bit safer when it comes to avoiding fraudulent material and spam.
Google has announced a few key changes for the Play Store that focus on cracking down on developers fraudulently promoting apps. The company is rolling out new detection and filtering tools, which should help it filter out attempts to manipulate the Play Store and its app rankings. The goal is to boost the integrity of the Play Store and its apps.
One example could be a developer or promoter installing apps to help boost that app’s presence within the Play Store. Google’s new systems should be able to spot that fraudulent behavior and filter it out entirely. The same filters should be able to capture spam reviews, as well as fraudulent incentivized ratings and reviews.
Developers that break the rules repeatedly can potentially have their app, or apps, pulled from the Play Store.
Source: Android Developers Blog