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What Are Cookies

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.
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