A web site can track a visitor's "click stream", what parts of a site you might visit, through use of a "cookie." A cookie is a text file that a Netscape or Microsoft browser makes that identifies what site you hit and gives you a unique identification tag for the cookie. Each cookie is stored in a basic text file on a web surfer's hard drive. If you use a PC and you use Netscape's Navigator, you have a file on your hard drive called "cookies.txt". If you have used more than one type of Netscape browser (like Netscape 3.0 and Netscape Gold 2.0) you will have more than one "cookies.txt" file. This file usually resides in the same folder the Netscape application is in.
Microsoft's cookie is store in its own folder called "Cookies." This folder usually resides in the "Windows" directory. In the folder, each cookie has its own file. Check it out - you can see them yourself.
The cookie is a stream of text that identifies you to a particular web site. A cookie can help a webmaster determine when you get to site, when you leave, and what pages you visit within the site. If the cookie is attached to a name, a site might greet you when you visit, even without logging in.
Cookies can also be used to store aggregate data about an individual. Infoseek pioneered using this technology. Infoseek tracks what keywords you search by so they can build up a profile of you over time. It stores this information encoded in your cookie file. For example, the value of my Infoseek cookie is "B94FD6E51D3352909227124F8A3D0AC3". Infoseek uses this information to serve up advertisements that you are more likely to respond to. For instance, since I do a lot of searches on Internet cutting-edge technology - I might be likely to see ads for high-tech internet magazines, web products, or computer hardware. I might even see high-tech ads when I search for information on the New York Yankees because Infoseek knows that I am still likely to respond to the ad.
Using cookies when programming web sites is fairly complicated, but they are transparent to the visitor.
Many people cry "big brother" when they first hear of cookies because they are uninformed. Cookies, themselves, are harmless. It is only a text file that resides on your hard drive. At any time, if you feel you are being watched too much, you can erase a cookie from the file. It is that easy.
Cookies, like any tool, could be misused by the unscrupulous. But then again, most frauds are committed via the telephone and I don't see people getting rid of that any time soon.