Back in 2007, when it bought ad network Doubleclick, the company told people that it wouldn't merge its massive database of Google account holders with the advertising service. The idea was that while Google would be able to use Doubleclick cookies to track you around the web it would not be able to connect that to, say, your Gmail account. The original wording said "We will not combine DoubleClick cookie information with personally identifiable information unless we have your opt-in consent". That data is now even more available if your privacy settings are not up-to-date. Head to the Ad Settings section of its privacy site and you can entirely disable personalisation.

Source: Daily Mirror February 05, 2019 09:49 UTC