Let's start by defining both cookies and how they are used to track your online behavior.

Cookies are small, plain-text files that reside on your computer and are managed by a web browser. If you have multiple web browsers installed on a single computer, each one maintains its own independent cache of cookies.

As web pages are downloaded to a computer, cookies typically come along for the ride. Likewise, as you make requests for new web pages, your web browser may upload a cookie as part of the web page request.