I know that Google is collecting much information with Analytics. Analytics uses first-party cookies, so Google shouldn't be able to recognize a person on different websites. How is the Cross-Domain-Tracking working?Let's say a person visits website A with GA and Google tracks it an stores the information on a server (Website sets first-party-cookie)Now the person visits website B with GA and Google tracks it again (Website B can't read the first-party-cookie of website A, Website B sets another first-party-cookie)Now the person visits website C with AdSense. How does Google know which advertisment they should show? Without third-party-cookies they can't know that the visitor was on the websites A and B before.
How does Google use analytics which uses first party cookies to show relevant ads on third party sites?
google analytics;google adsense;tracking
Google does not use Google Analytics for the purpose of choosing which ads to show.Google AdSense ads set their own third party cookies.  Google tracks users across multiple domains with cookies set by ads, not with cookies set by Google Analytics.