Facebook has been granted patent on shadow banning

Despite its frequent denials that it practices “shadowbanning” — the covert censorship of content without notifying the censored — Facebok applied for and received a U.S. patent for shadowbanning technology last month, according to a report in the New American.

  Source

 https://news.ycombinator.com/item?id=20647592

https://gizmodo.com/facebook-patents-shadowbanning-1836411346