In accordance with the Electronic Communications Act anyone who visits a website with cookies shall be informed about the usage and storing of said cookies.
A cookie is a small text based computer file that a web server can request to save on a visitors computer. By adding a cookie to your computer it is possible for the web server to recognize and retrieve things like the visitors personal settings used on that specific website.
Cookies kan contain information in human readable text (e.g. you language preferences), however, most of the time the information in a cookie file is encrypted. Usually a cookie only contains a key to a post on a web server.
A cookie can contain an expiration date. Depending on your browser and its settings a cookie can be stored on you hardrive for future use or temporarily in your RAM. In the latter case the cookie is not stored for future use and expires once the browser is closed and is usually referred to as a session cookie.
By using cookies it is possible to track a visitors usage habits and other aspects of the visitors general trafik behavior on a website. As such it is commonly used for statistical and and analytical purposes to improve usability on said website.
Common misconceptions about cookies are that they are some sort of computer virus, that they can retrieve personal information from your computer or that they are used for spam mail. Non of this is of course true. Cookies are simple data stored for your convenience!