Are Computer Cookies Harmful ?
by Milton Kazmeyer, Demand Media
Cookies are bits of information sites store on your computer to aid in browsing.
When you browse the Web, sites sometimes store information on your computer to aid in your browsing session. These small text files, called cookies, may seem innocuous, and most of them are completely harmless. But some advertisers have developed methods of using cookies to track your browsing habits, and understanding how these work can help you maintain your privacy online.
When you access a website, your browser gives that site the authority to store data on your computer. This data can serve several different purposes, and many of them are completely legitimate. For example, if you visit a website that requires a login and password, the site may store that information on your computer so it doesn’t have to ask you to log in for each page you visit. If you shop online, a site may store a cookie containing information about your shopping cart, or a site may store other preference data using one of these text files.
A tracking cookie comes about because one site may contain content from several sources. When a company places an advertisement on a Web page, this ad gives its server the ability to place its own cookies on your system. A tracking cookie contains information about what ad you viewed and the website where you viewed it. If you visit another site served by that advertiser, it can check that cookie and see which two sites you visited to view that particular ad. This lets the company build up tracking information, learning which sites have similar audiences so it can better target its advertising.
By itself, a tracking cookie is harmless. Without providing any information to the advertiser that set the cookie, the site has no identifying information to store in the text file, so any data the company tracks will be anonymous. An advertiser may be able to link together several websites you visit regularly but will have no way of connecting that data to your real world identity. If you do business with a company that sells its customer information to advertisers, however, this data may provide some identity information to the company and let them to target you for mail or other advertising.
Several techniques will prohibit cookie-based tracking. You can set your browser to reject all cookies, but this practice can cause some websites to malfunction. You can regularly clear out your cookies using your browser’s configuration settings, but this flushing will also reset any website that stores passwords or preference information in cookie form. Your browser may also have an option to disallow third-party or tracking cookies, and enabling this will prevent these companies from being able to set cookies when their ads appear on other pages.
Source: Opposing Views