Cookies are small files that Web servers place on a user's hard drive.
They can serve several functions:
they allow the web site 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
web sites 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 web sites; and
they can be used to help a web site tailor screens for each
Cookies can be temporary or persistent. Temporary cookies exist only
while your web browser is active; when you close your browser they cease to exist.
Persistent cookies are saved in files
on your hard drive and can be transmitted to websites requesting them. Closing your
browser does not get rid of them. All of this is done behind the scenes.