Web sites store "cookies" on your computer
to keep track of information about your activity on the site. Cookies
are named after magic cookies, the data objects exchanged by computer processes
on Unix computers to establish
various authorizations. Web cookies were also called "magic
cookies" when they were first introduced.
A cookie is a small text file stored by a web site on your computer
to keep track of information about your browsing on that site.
A simple example is shown below:
# Example Cookie
# Recorded 2000-10-12
username=John
password=treeline8
frames=yes
If you use Microsoft Internet Explorer, your cookies are kept
as individual files in a folder named "Cookies", often
found in the "Documents and Settings" folder, If you
use Mozilla Firefox, your cookies are stored in a text file named
"cookies",
often found in
the "Firefox/Profiles"
folder.
Some of the reasons web sites use cookies are described below:
- Customization. Some sites use cookies
to record your surfing patterns, and then optimize the information the
site subsequently presents. For example, a search site may present you
with advertising that reflects
your interests based on the keywords you search
for.
- Distribution. One of the key reasons
web sites use cookies is to distribute the information storage. A cookie
takes up a small amount of space on an individual computer, but would take
up a very
large amount of space if they all had to be stored back
on a web site's server.
- Security. If a cookie was stored
on a web site, then it can be accessed by anyone with access to that web
site. However, when the cookie is stored on your computer, then it can't
be accessed by hackers that break into the web site.
- Privacy. If a cookie was stored on a web
site, then you would have to identify yourself somehow so the site would
know which cookie to give you. But when the cookie is stored on your computer,
then the web site simply uses
whatever cookie it finds without requiring disclosure of your identity.