Cookies are pieces of information generated by a Web server and stored in the user's computer.
Cookies make use of user-specific information transmitted by the Web server onto the user's computer so that the information might be available for later access by itself or other servers. The storage of personal information into a cookie usually goes unnoticed as does access to it. A cookie cannot be used to get data from your hard drive, get your email address or steal sensitive information about you. A cookie can be used to track where you travel over a particular site. This site tracking can be done easily without using cookies, but cookies make the tracking data a little more consistent.