What is a cookie?

A "cookie" is a small, customised piece of information that a Website can store locally on your hard drive. The information is stored as a text file, with a maximum size of 4K and 255 characters.

How do they work?

Cookies are stored, accessed, and deleted through your browser software. When you start up your browser, the cookies stored on your machine are read in. When you close your browser, any new cookies are saved to your hard drive, and cookies that have expired are deleted. Your browser will store only a limited number of cookies, and once that number is reached the oldest cookies are deleted to make room for new ones.

Why do Websites use them?

Most Websites use cookies to remember information about individual visitors, such as names, passwords, or areas of interest. Some reasons sites use cookies are:

 customised Web pages for each visitor
 internal feedback on what visitors do and don't like
 shopping baskets (tracking your purchases from page to page)
 secure pages for "members only"
 intelligent forms
 targeted advertising

Are cookies a security risk?

Cookies are simply text files. They can't collect anything - they just store information that you provide. They cannot read your hard drive to discover your name, where you live, or your credit card details. If you type in your e-mail name or credit card details, this information could be stored as a cookie on your computer, but this is no more or less secure than typing the information over the Web in the first place. Each cookie is associated with the domain name that created it, and will only give up its information to the same domain name.

Where are cookies stored?

Browsers store cookies in their Preferences folder:

Netscape (Windows)	cookies.txt file
Netscape (Mac)	MagicCookie file
Explorer (Windows)	Windows\Cookies directory
Explorer (Mac)	Explorer folder

What if I don't want to accept cookies?

Your browser lets you choose whether to accept cookies. There are three options: always accept / never accept / warn before accepting

Can I delete cookies from my hard drive?

You can delete the cookie file on your hard drive, but you lose the benefit of having information that could improve your browsing experience. Deleting all your cookies will return you to "new visitor" status with sites you visit frequently. Be sure to close your browser before editing your cookie file, as cookies are stored in memory and will be rewritten when the browser is closed.

It may be advisable to delete only those cookies that you don't want. Software such as Window Washer or Cookie Monster can help you keep on top of cookies.