Academic Project Used Marketing Data to Monitor Russian Military Sites - WSJ

The researchers’ experiment underscores how the global marketing industry’s practice of collecting and reselling reams of user data, often for marketing and advertising purposes, can be turned toward other ends. The data can be easily purchased and exploited by foreign and domestic national-security agencies, law-enforcement officials and others for surveillance and monitoring.

Another reason why users should rejoice as new system level privacy protections are released and whenever advertisers object and complain.