Cookies are small files that Web servers place on a visiter's hard drive. This is done using a "Script" in the source code, which is active content. They can serve several functions:
- they allow the Website to identify you as a previous visitor each time you access a site;
- they track what information you view at a site (important to commercial sites trying to determine your buying preferences);
- in the more advanced cases they track your movements through many Websites but not the whole Web;
- businesses use them for customer convenience to allow them to produce a list of items to buy and pay for them all at one time and to garner information about what individuals are buying at their sites;
- advertisers use them to determine the effectiveness of their marketing and offer insights into consumer preferences and tastes by collecting data from many Websites; and
- they can be used to help a Website tailor screens for each customer's preference.