A leading privacy group filed a formal complaint on Thursday with the Federal Trade Commission over a 2012 study in which Facebook manipulated the news feeds of nearly 700,000 users of the social network to see what effect the changes would have on their emotions.The group, the Electronic Privacy Information Center, said Facebook had deceived its users and violated the terms of a 2012 consent decree with the F.T.C., which is the principal regulatory agency overseeing consumer privacy in the United States.
http://bits.blogs.nytimes.com/2014/07/03/privacy-group-complains-to-f-t-c-about-facebook-emotion-study/