A cookie is an identifying tag that is handed out to users via the Web site's server. Many browsers store the tag so that when the user logs on the next time, the server will identify the person from his or her last visit. Cookies don't allow the server to know personal information unless the user filled out a previous registration form. Cookies are mainly a help to marketers who want to know how often individuals are returning, what they read and what they purchase. The information can greatly help marketers and designers know which areas of the site and which products are popular, and which are not.
Servers create records of everything that happens on the server.
These are called log files. The server creates one massive file containing every activity that occurred on the server. If your server is housed elsewhere, ask your Internet service provider about obtaining such logs. To exploit the information that is collected, you can either thumb through it line by line or purchase software that crunches down the information to create more meaningful data. Software tools can also reconstruct the usage patterns that individual visitors took during a particular visit.