https://www.theguardian.com/technology/2016/oct/21/how-to-disable-google-ad-tracking-gmail-youtube-browser-history
In practice, this means that Google can now, if it wanted to, build up even richer profiles of named individuals’ online activity. It also means that the DoubleClick ads that follow people on the web could be personalized based on the keywords that individuals use in Gmail.
