What is a tracking cookie ?

A tracking cookie (or "online activity tracker") is a snippet of computer code that is added to your browser's storage. Regular Internet users likely have a long list of these trackers, unwittingly picked up when visiting certain sites or clicking on ads.

This code, known as a "cookie," allows companies to access your personal information and arms them with the ability to observe and store your online behavior.

What types of information do they gather?