Cookies help Web sites maintain user states.
Cookies are small data structures delivered by a Web site to a Web client.
The Web site may deliver one or more cookies to the client. The client stores cookie data in one or more flat files on its local hard drive. Cookies allow Web sites to maintain information on a particular user across HTTP connections. In some cases it is useful to maintain state information about the user across HTTP transactions. User information may be stored in the cookie or in a database on the Web site.