Cookies
Cookies are a mechanism which allows server side connections (such as CGI scripts) to both store and retrieve information on the client side of the connection. Listed below are several links to more detailed explanations about cookies.
Netscape's Specification: Persistent Client State HTTP Cookies
Andy's Netscape HTTP Cookie Notes
Malcolm's Guide to Persistent Cookies
Cookie Central
Malcolm's Guide to Persistent Cookies resources
Who's Watching You and What are You Telling Them??