I’ve been told that when I go to websites, they leave behind cookies on my computer. What are they doing? How can I stop them?
Cookies are small files that a website can place on your computer; cookies are supported by most of the major web browsers. Cookies serve all sorts of purposes, such as identifying users, maintaining state, and storing preferences.
Cookies identify users by allowing a web site to place a unique identifier such as an id number on your computer. When you return to the web site or move to a new page, the site reads the ID from the cookie and reloads your records. Advertisers can use cookies to track the ads you see, and webmasters can use cookies to record how many times you visit their sites.
Cookies often have an evil connotation, but they are not always bad. How does Amazon remember what is in your shopping cart? They use information stored in a cookie to identify you and bring up your cart as you browse their site. Without maintaining state, you would have to re-enter your password every time you load a new page, click a different link or download another file from any website that requires you to log in. Online banking, web-based e-mail and subscription-based online publications are all examples of sites that must maintain state in order to operate effectively.
Cookies are a way for a website to uniquely identify a computer, but I do not intend to give the impression that they are some sort of evil device. Firstly, one website cannot read another’s cookies. Amazon cannot retrieve your online banking information by reading your bank’s cookies. Secondly, a cookie cannot magically link you and your computer to your social security records — on the other hand, a cookie probably will enable a site to remember any information that you willingly surrender. For this reason, you should always be conscious of the information you put online.
Since cookies are a tool for “remembering” information, they are also used to store preferences. If you use a website that allows you to select a custom language, font, color scheme etc. then there’s a good chance that data is stored in a cookie, to be reloaded each time you return.
Erase cookies
- Internet Explorer (IE): Click Tools, click Internet Options, click Delete Cookies.
- Firefox: Click Tools, click Clear Private Data, check off Cookies and press Clear Private Data Now.
- Opera: Click File, click Delete Private Data.
- Safari: Click Safari, click Preferences, go to the Security tab, click Show Cookies, click Remove All.
By deleting the cookies stored on your system, you will lose your preferences and logins accross all of the websites that you use daily. You will find that you are logged out of sites like web-based e-mail, and the regular sites that you read do not remember your preferences for style, color and fonts.
Limit cookies
Most browsers have privacy features that allow you to limit the freedom websites have with regards to placing cookies on your machine.
- Internet Explorer (IE): Click Tools, click Internet Options, go to the Privacy tab and adjust the security level to your liking.
- Firefox: Click Tools, click Options, click the Privacy icon, click Cookies and adjust the security level to your liking.
- Opera: Click File, click Preferences, click Privacy and adjust the security level to your liking.
- Safari: Click Safari, click Preferences, click Security and adjust the security level to your liking.
By limiting or disallowing the freedom of a website to utilize cookies, you may miss out on some interactive features of certain websites. For instance, you may not be able to log into your e-mail or online banking. Many websites may present you with a warning that cookies are required for operation.
