A cookie is a small piece of information written to the hard drive of an Internet user when he or she visits a website that offers cookies. Cookie files are extremely small, comprising no more than 255 characters and 4k of disk space. Cookies can contain a variety of information, including the name of the website that issued them, where on the site the user visited, passwords, and even user names and credit card numbers that have been supplied via forms. Cookies are supposedly only retrievable by the site that issued them and link the information gathered to a unique ID number assigned to the cookie so that information is available from one session to another. What users should know.
Cookies offer many benefits for Internet users.
One benefit is that cookies store information. This way, repeat visitors to a site could avoid having to fill out form information on each visit. Likewise, some online search engines such as use cookies to remember users and offer them customized news and services based on their prior use. For example, instead of having to send a credit card number over the Internet multiple times, an online vendor could read the user's cookie and match it to a stored profile which would contain that information. Also, cookies that traced user activity on websites could also enable the web designers to determine which of their pages were the most successful and plan their updates accordingly.