What are Computer Cookies?

Cookies — also called Web cookies — are a small piece of text that is sent to a browser by a Web server that contain information that is used by the server to track details of the user's activities on a given site.

They often contain a record of your last visit date and time, or the contents of your shopping cart on shopping sites, but can also contain other information.

Cookies are not programs — they do not "run" on your computer — rather, they provide information to the Web server that you connect to. Despite that fact, many anti-virus programs treat Web cookies as if they are programs, often warning the user about the existence of certain cookies on the system. In cases such as this, the warning is related to the fact that a cookie may be used to track your access to various sites that utilize it, which is why the security program declares it suspect.

When a Web site warns you that cookies must be enabled to use that site, it is usually not a security issue, but rather a functional issue. The site may be using the cookies to determine what content to show you, or to authorize your access to deeper sections of the site once you leave the main page.

Web cookies are one of the most misunderstood parts of surfing the net — so here are the facts about the most popular myths:

Cookies are not used to inject virus' into your computer.
Cookies are not used to cause pop-ups to appear on your computer.
Cookies do not take control of your computer or browser.
Cookies will not slow down your computer.
Cookies do not delete files on your computer.
Deleting cookies will not damage your browser or computer.
You do not need a special program to "manage" cookies.

One concern widely felt that is valid is the question of privacy — cookies can and often do identify the user of the computer to the site that is being visited. Some sites use cookies to store the user name and password for their site so that you do not have to constantly enter this information each time you visit. This can be problematic if you use public-access points, such as WiFi.

Any unencrypted transaction at a WiFi hotspot can be intercepted using easily obtained software that can be downloaded from the web. When using a WiFi hotspot, verify that your connection is using WPA or higher encryption, or refrain from using sites that remember your password for you.