About Cookies

A cookie is a small file that a website sends to your PC when you browse the Internet. Cookies are stored as text files on your hard drive so that servers can access them when you return to web sites you've visited before.

Cookies contain information that identifies a user. For example: username, passwords, shopping cart information, preferences, and so on can be stored in a cookie. When a user revisits a web site, his or her computer automatically "serves up" the cookie, which establishes the user's identity, thus eliminating the need for the customer to reenter the information on that website. Basically, the server needs to know this information in order for the web site to work correctly.

Cookies are commonly used when you, as a user, login to a web site where you've registered a username and password. The server finds the cookie information on your computer, checks with its own information, and if they match, retrieves your file. You then have easy access to your online account. 

Examples

For example, when you purchase airline tickets online, cookies ensure that you do not have to reenter your frequent flyer number each time you revisit an airline website.

Cookie technology also makes shopping cart technology possible. For example, when you select items that you intend to purchase in an online shop or catalog, cookies make it possible for you to continue shopping and to "check-out" later. When you go to the order form, the items you selected miraculously appear.

Within the Internet industry, cookies are used by advertisers to track your browsing and buying habits. This enables advertisers to target ads based on what your interests are (see Adware). Cookies allow Amazon.com, for example, to tailor its appearance to suit a user's established preferences.

What Does It Mean For Me?

This is a double-edged sword for many people, because on the one hand, it's efficient in that you only see ads about what you're interested in. On the other hand, it involves actually "tracking" and "following" where you go and what you click on. This tracking and following facilitates the delivery of advertisements to your computer (see Spyware).

Tracking cookies, when used in conjunction with other "ad delivery" software can affect your PC's performance and leave you at risk for viruses and other malicious programs.