If you go to a web site and register your name and password (like you probably did with AccountingWEB, a small file called a "cookie" is left on your computer. The next time you go to the web site, the site recognizes you and you gain instant access. The site recognizes you because it has found the cookie.
You may notice that if you are using a different computer and you try to go to a site on which you have registered, you have to provide your registration information again. Or, the cookie feature may be turned off entirely on your computer, which means that no matter how many times you register, each time you return to a site requiring registration, you have to do it again.
There are two types of cookies that can be placed on your computer. First party cookies are those you asked for – like the registration information you entered on a site. Third party cookies just come along for the ride, even if you do nothing. An example of a third-party might be an advertiser who places ads on web sites. Some advertisers will add their own cookies to your computer when you display the ad.
A new software add-on from Microsoft works with Microsoft Explorer to enable you to request that cookies be described to you before they are saved and gives you the option of refusing third-party cookies. The Microsoft program explains the cookie information to you before you choose to block, describing how the cookie's placement enables the third-party to recognize you.
Netscape also offers such a program, which enables the user to accept all cookies, block all cookies, or block third-party cookies.
Electronic privacy advocates are pleased with a new opportunity to prevent advertisers from building a profile of a user based on sites the user visited.