Up until recently, Google collected your data but never directly tied your identity to it. It has since lifted the ban on personally identifiable web tracking and can now use all of the information collected from your searches, your email, Youtube, Maps, and all of Google’s affiliates, to build a comprehensive profile on you.
In 2007, when Google bought the advertising network DoubleClick, Google founder Sergey Brin made privacy the company’s number one priority while contemplating new kinds of advertising products. DoubleClick’s database of web-browsing records was kept separate from personal information collected by Google, but now your browsing habits “may be” used in conjunction with what the company knows about you.
This means that the DoubleClick ads you see while browsing could be customized to you based on your name and other personal identifiers. The scarier consequence to this is that Google can now build a profile of any user according to their name and based on everything they write in an email, every website they visit and every search they conduct.
There is a way to opt out of this, however.
To opt-out of Google’s identified tracking, visit the Activity controls on Google’s My Account page, and uncheck the box next to “Include Chrome browsing history and activity from websites and apps that use Google services.”
You can also delete past activity from your account.