Your data on the web 
… and
how it makes websites more useful
Say you go to the same coffee shop every morning for a latte and the same barista makes it for you every day. Chances are he’ll know your order before you even walk through the door. Websites, including Google, have learned a lot from this relationship. We’ve learned that we can serve you better if we get to know you better.
When the web first
started, it was a set of static pages that looked the same for everybody. Nowadays, the
web has become even more useful because websites can know something about you that helps
them guess what you would like to view. For example, they can remember whether you want
them in English or French, can suggest books or movies you might enjoy based on what
you’ve viewed in the past, and can store your delivery address ready for your next
purchase.
There are many clues that websites can use to guess your preferences, including cookies, IP addresses, and signing in with an account.
Read the first topic: How cookies help websites remember your preferences