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Cookies are small files a web site puts on your computer to store information about you for them. The following sections describe what they are, what they can do, and what you can do about them:
What Are Cookies - Little text files stored on
your machine.
Cookie Capabilities - What cookies can and can't do.
Avoiding Cookies - Browser settings and third-party solutions.
What Are Cookies
A web site stores a cookie on your computer to keep track of information about your activity on that 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 you. A simple example cookie for an imaginary web site is shown below:
# Example Cookie
# Recorded 2000-10-12
username=pradeep
password=pk123
frames=yes
If you use Netscape Communicator, your cookie file can be found in a path something like:
C:\Program Files\Netscape\Users\<your user
name>\cookies.txt
If you use Microsoft Internet Explorer, your cookies are kept in an operating
system file.
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.
Cookie Capabilities
A summary of cookie capabilities is given below:
Default settings. Cookies can store useful
information by setting your default settings for a site every time you visit,
such as your user name and password, preference settings, etc.
Custom content. If you search for words associated with a certain subject,
such as "garden", the site can learn to present you with information
on gardening related subjects.
Form data. Cookies can be used to archive information that you enter
on forms, so that if you leave the page or you become disconnected and come
back to the page later, your previously entered data can be preloaded for you.
Limitations. Cookies cannot access your email address, read files from
your hard drive, or obtain your credit card numbers or other personal information.
Cookies cannot put viruses on your computer, because they are just text data
files and not programs.
Cross-site access. Cookies from one site cannot be used to record your
activity on other sites, and sites cannot read other sites cookies. Other than
site specific activity a site cannot access any other information - with two
exceptions. A site can record the address of the site you linked from,
and it can record the address of the site you link to.
You can prevent cookies from being used on your computer, or manage them with a custom application. You can set your browser to reject cookies as follows.
Internet Explorer. Select Tools/InternetOptions/Security, and set the security level to "High".
Netscape Communicator. Select Edit/Preferences/Advanced, and set "Cookies" to "Disable cookies".
Note that some web sites won't yet you visit unless you accept their cookies. If you want to go to the trouble, you can turn cookies on to visit them, turn them off when you leave, and then turn them back on when you return, whereupon you may have to re-enter information not saved in the cookie.
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