What is a Cookie?
Basically, a Cookie is a very simple text file whose composition depends directly on the contents of the visited Web address. For example, most sites store basic information such as IP addresses and preferences about languages, colors, etc. However, in portals like Gmail and Hotmail, user names and email passwords are also part of the Cookies.
How does Cookie work?
When you visit a site for the first time, it sends a Cookie as a response to your browser, containing your preferences, in text format. This small file will be stored on your computer until it loses its validity.
While the cookie is saved on your PC, every time you enter the site address, your browser will send this file to the site you are connected to. In this way, your settings will be applied automatically.