https://techcrunch.com/2019/08/06/facebook-still-full-of-groups-trading-fake-reviews-says-consumer-group/

Facebook has failed to clean up the brisk trade in fake product reviews taking place on its platform, an investigation by the consumer association Which? has found.

In June both Facebook and eBay were warned by the UK’s Competition and Markets Authority (CMA) they needed to do more to tackle the sale of fake product reviews. On eBay sellers were offering batches of five-star product reviews in exchange for cash, while Facebook’s platform was found hosting multiple groups were members solicited writers of fake reviews in exchange for free products or cash (or both).