The algorithm at the heart of the Facebook data breach sounds almost too dystopian to be real. It trawls through the most apparently trivial, throwaway postings –the “likes” users dole out as they browse the site – to gather sensitive personal information about sexual orientation, race, gender, even intelligence and childhood trauma.A few dozen “likes” can give a strong prediction of which party a user will vote for, reveal their gender and whether their partner is likely to be a man or woman, provide powerful clues about whether their parents stayed together throughout their childhood and predict their vulnerability to substance abuse. And it can do all this without delving into personal messages, posts, status updates, photos or all the other information Facebook holds.

Source: How Cambridge Analytica turned Facebook ‘likes’ into a lucrative political tool | Technology | The Guardian