If you want to learn more you can Google the top vendors in the DMP space: Krux (now Salesforce DMP), BlueKai, LiveRamp, DataLogix, Acxiom [sic.] A couple of th

If you want to learn more you can Google the top vendors in the DMP space: Krux (now Salesforce DMP), BlueKai, LiveRamp, DataLogix, Acxiom [sic.] A couple of these offer "CRM Onboarding" (matching real names/addresses to anonymous cookies) but it doesn't work very well in practice and the real product is pools of anonymous cookies where even basic demographics like age and gender are unknown and can only be (badly) inferred. As far as I know, none of these companies offer any services in the "law-enforcement/government/political online surveillance" space you mention but I've never really researched that side of it.