These companies, according to a 2013 study by computational psychologist and big data scientist Michal Kosinski and others, found that Facebook likes "can be used to automatically and accurately predict a range of highly sensitive personal attributes."
Kosinski's algorithm was able to predict whether a person was black or white with 95% accuracy, male or female with 93% accuracy, gay or straight with 88% accuracy and Democrat or Republican with 85% accuracy.
With just 10 likes, a computer model fundamentally knows you better than a colleague, according to additional research published by Kosinski in 2015. With 70 likes, it knows you better than a friend or roommate; with 150 likes, better than a family member. And with 300 likes, Big Data knows you better than your spouse.