Cookies are small text files that web pages place on your computer when you visit a web page. The
text file contains information that helps web pages track users and allows site preferences so that
when you re-enter a page, itís unique to your custom settings or has "one-click" purchase options.
How Cookies Work
When you visit a website that tracks user data in this way, the site "drops a cookie" and creates a text
file on your machine if it is your first visit, or updates a file that it left on your machine from a previous
visit. The website does not change anything on your computer other than the file and, in all but
the rarest of cases, the cookie does not contain any private information such as credit card numbers
or home addresses and phone number. Most often, the cookie contains only the name of the web
page and a unique identifier that the web page uses to pull information from a secure database where
the private information about you is kept. This helps prevent problems associated with different people
sharing the same machine, or a single user who switches between machines. It also allows web
pages to keep track of users even when they have deleted all their cookie files.
Not all cookies are bad things. For example, http://www.weather.com may place a cookie on your
computer to store your ZIP code so that each time you return to its website, it can immediately bring
up the local weather for your location.
However, one of the main issues with cookies is that marketing companies often use information about
what you buy and where you click on a web page to better target you for advertising and spam. Some
cookies are tracked across multiple sites by third-party companies. This is considered a privacy or security
violation by many users. To protect your personal information, you can set your Internet browser to one
of various privacy settings ranging from accept all cookies to block all cookies. Both these options
are a bit impractical because accepting all will greatly increase security risks and blocking all will
make it very difficult to browse many private and commercial websites (the pages will fail to load).
On Internet Explorer, we recommend a setting of Medium High as Figure 16-1 shows. (The screen is
found by selecting the Privacy tab on the Internet Options dialog box, which is found under the Tools
drop-down menu on the top of the browser.)
If you are worried about the cookies you have previously accepted, you can delete all cookies by
selecting the Delete Cookies button on the General screen of the window shown in Figure 16-1. If
you had your privacy setting set to anything below Medium High, you should probably do this when
you reset your settings.