Reddit

Reddit sold years of user conversations to AI companies for training data, a practice its privacy policy still permits without user consent. Its mobile app tracks browsing behavior 40% more aggressively than its website, compiling interest profiles that predict your preferences with eerie accuracy. Among the platforms on this list, Reddit is less invasive than Pinterest in third-party data sharing, but its sale of user posts—over 20 million comments sold in 2023 alone—makes it a significant privacy threat.