I do this research every day. So I’m guessing you’ve heard about this. tl;dr : Scientists at Facebook manipulated the posts they showed certain users and then evaluated the posts the people being manipulated made. Then they published a study on the results.
A lot of people are reacting very strongly to this news.
Some people are pissed at the idea of being manipulated. While I empathize and agree, I think a lot of their anger is based on a contract with Facebook that Facebook abandoned a long time ago.