The Web cookie is a small text file that is transferred to the user's computer during his visit to the site and usually contains:
Name of the server that sent the cookie;
Lifetime of the cookies;
Value - usually random generated unique number.
The cookie itself contains or collects information. It reads the server along with the Web search engine, which is a helpful for the friendly services to the user on the Web - eg so that he remembers previous purchases or data about the user's account. Only the server that sent the cookie can read the cookie and use it. On the trusted website, the cookies enrich the experience. Sometimes this action is done in the privacy. The cookies can be stored differently long, sometimes just for surfing the web or longer.