Whose service are you talking about? If you use a browser and don't block third-party trackers, Google will know about 60% of the websites you visit, and Faceb

Whose service are you talking about? If you use a browser and don't block third-party trackers, Google will know about 60% of the websites you visit, and Facebook about 20%. Even if you never signed up to any of their services and don't use any of their offerings.