Passage: The Chinese government aims at assessing the trustworthiness and compliance of each person. The data collected stems both from peoples' own accounts, as well as their network's activities. Website operators can mine the traces of data that users exchange with websites and derive a full social profile that includes location, friends, health records, insurance, private messages, financial position, gaming duration, smart home statistics, preferred newspapers, shopping history, and dating behaviour.

Question: what can websites mine?
traces of data