Can Cookies Hurt My Computer?

Everyone loves cookies, right? They may not be good for us, but they sure taste yummy. So why do computer cookies, which are not only calorie-free but actually helpful, have such a bad rap?

Cookies are not viruses, worms, or Trojan horses, nor do they transmit such threats to your computer. They are not harmful, and in fact, their purpose is to make your visits to websites faster, easier, and smoother.

A computer cookie is a cute name for a useful piece of information, packaged to be read by websites. The information contained in a cookie pertains to you and your computer use. Suppose you've registered with a certain website. During the registration process, the website dropped a cookie onto your hard disk. Thanks to the cookie, you won't have to re-register the next time you visit the website or even re-enter your name and password.

Like helpful elves, cookies also help take care of certain bits of repetitious computer "housekeeping" that enable Web pages to load more smoothly and rapidly. And cookies can be invaluable for services such as shopping carts and coupons, remembering what you've previously purchased and the address to which you sent it. So far, so good—and the vast majority of cookies are good, terrifically helpful tools that make the Web easier to use. There are a few issues to be aware of, however:

• First-Party Cookies, those created by the websites you visit, are generally considered to be legitimate uses of personal information (your password for that site, for example).
• Third-Party Cookies, which are created by, say, an advertiser on your favorite site, are a bit more ambiguous. They track your Web surfing habits—also a type of personal information—and feed the data back to the advertisers. If you object to such use of information about your Web activities, then you have a few options: You can set your browser to refuse third-party cookies, you can periodically delete your cookies (to do so, click on the Tools menu in most browsers, then select Options and look for General or Privacy settings), or you can run security software that alerts you to the presence of tracking cookies and allows you to decide whether to delete them.

Cookie Poisoning happens when hackers gain access to the files where your cookie information is stored on your computer. Because some of this information is material like passwords and account numbers, losing the information or having it changed by an outsider can expose you to identity theft. Cookie poisoning is rare, but it further validates constant vigilance and use of anti-virus, anti-spyware, and other protective software.

Follow-up: Cookies are good; they make the Internet work. But if you'd prefer to limit the number of cookies you receive and the sensitive information they may contain, take precautions such as not registering at websites unless you intend to visit them regularly.