Avoid the Indigestion of Cookies
You may have heard of cookies, a cute name for a tiny piece of code that is
stored on your computer when you visit some websites. Cookies contain information
such as whether you are a new or a returning visitor, and if you are a returning
visitor, they will let the website know who you are. Due to their very nature,
cookies can not harm your computer, either by stealing any of your information
or storing a virus. They simply hold information you usually would have saved yourself.
In most cases, cookies are harmless, and are often necessary on some sites.
For instance, if you regularly go to your favorite website, but you always have
to sign in, you may check a checkbox such as "Save my login and password." The
next time you visit, you can bypass the login information. That is because your
information has been saved and encrpyted into a cookie just for this purpose.
Cookies were originally created to help the website "remember" who you are
and what you have done. Whenever you look at a web page, the web server that
stores the website and sent you this webpage immediately forgets who you are.
This is designed to save computing power, especially if thousands of people are
visiting the website at once.
By using a cookie, when you surf to another page within the site, the web
server checks the cookie to see what you had previously done on this site. An
obvious use for this is an ecommerce site. If you are ordering multiple items,
they are stored in an electronic shopping cart. Without cookies, if you tried
ordering a second item, the first item would suddenly disappear, because the
website wouldn't know who you are.
When you leave the site, the cookie that was used to track your shopping cart
is immediately destroyed (this is a "session" cookie.) Other cookies remain on
your machine (they are "persistant"), such as if you check the box to remember
your login for next time. There is a limit to how many cookies can be on your
machine, so older persistant cookies that have not been called in a while will
eventually be pushed out and erased to make way for more recent ones.
Cookies that May Give You Indigestion
use them to track who you are and where you go. This has obvious privacy concerns.
Large online advertising networks may span hundreds of websites, such as those
with flashy banner ads like "Hit the Monkey and Win Something!"
What happens is that this advertiser's cookie is stored on your machine, and
when you next visit a different site with the same company's ad, the programming
in the banner checks to see if their cookie exists on your machine. Since it will,
the advertising network will then know the two sites you went to, and begin to
build a profile of what you visit. They can then begin to tailor their ads to
your interests. For instance, if you often visit vacation sites, the banner ad
will begin showing you advertisements for travel offers.