Facebook is a leading technological company. Its most influential products include Facebook platform, Face messenger, Instagram, WhatsApp and Oculus.
Before an election in November 2010 in US, Facebook implemented a button "I voted" allowing people to share with their friends if they participated to the election. The study publish in 2012 in Nature BondFJKMSF-12 shows that the simple fact of adding profile pictures of up to six randomly selected Facebook friends who had clicked the "I voted" button increase the chance of people to also click on the "I voted" buttons later. This experiment seems to show that social network decisions may have a big influence in our world.
Emotional contagion experiment
In 2014, researchers from the Facebook Core Data Science Team published a paper about emotional contagion experiment KramerGJH-14.
The experiment was conducted on 689.000 real users and shows that it was possible to observe a change in the proportion of positive or negative words contained in user posts by slightly changing the content of their news feed. Although the effect sizes from the manipulations are small, the experiments took place for only one week.
After the publication of this paper, Facebook had to apologize for this study WASH-14 after many academics (and the public) raised concerns and the Proceedings of the National Academy of Sciences published an editorial concern PNAS-14.
A study from 2018 shows that is was possible to predict depression from the history of Facebook statuses EichstaedtaSMUCPAS-18. By using language analysis from Facebook posts of consenting individuals, they were able to predict depression recorded in electronic medical records with a fair accuracy [area under the curve (AUC)=0.69].