FB-largest collective social media platform, owned & operated by C_A. MZ is a C_A operative. DARPA ended and FB launched on the same day, 4 Mar 2004
FB uses microphone, camera and GPS 1-to listen to 2-view & record, 3-track 4-analyze users & their friends
Cambridge Analytica Ltd (CA) was a British political consulting firm which combined data mining, data brokerage, and data analysis with strategic communication during the electoral processes. It was started in 2013 as an offshoot of the SCL Group.The company closed operations in 2018 in the course of the Facebook–Cambridge Analytica data scandal, although related firms still exist
https://en.wikipedia.org/wiki/Cambridge_Analytica
Cambridge Analytica harvested FB users & their friends public info and private messages to build psychological profiles for "voters".
Other apps: Duolingo, Indeed, Yelp, King James Bible apps, Qibla Connect & Muslim Pro harvest and send users info to FB with/without users consent/knowledge, even though they may not have or never had FB installed on their device. There were other apps doing the same thing, but, supposedly, they have fixed the problem.
FB has the help of their human users to help filter through likes/dislikes to rank/review popular posts with the use of the LIKE button. This helped FB to understand that certain words and phrases helped the post to gain more likes ex: forward, retweet (Where have i seen this?)