Cookies and Their Uses

Cookies are small fragments of text that a Web site can send to a user’s computer. They are stored in a file (cookies.txt) on the user’s machine and can be recalled when the user revisits the site.

Each cookie is associated with a particular Web site, and cookies can only be retrieved by the site that sent them. Cookies that msn.com places on a user’s machine, for example, cannot be accessed by a page on yahoo.com. Cookies cannot transmit personal data to a site that the user has not already supplied to the site. A common use of cookies is to store usernames and passwords (usually in encrypted form). When the user enters his name and password and clicks a box indicating that he wants to log in automatically when he returns to the site, the site places a cookie on his computer to identify that particular user. When the user returns to the site, the site requests the cookie. If the user has the appropriate cookie, he can enter the site without being required to enter his username and password again.