Cookies are small text files on your system, used for keeping track of settings or data for a particular Web site. Because the servers that receive your requests for Web pages have no way of knowing specifically who is making a request, they have no way of storing settings for specific users or changing the page they send based on choices a user has made on another page.

Cookies solve this problem by saving settings on your (the user's) system. When your browser requests a page, it sends the settings that apply to that page along with the request. Because your browser will send back only the settings to the server that originally created them, cookies are a very secure way of maintaining data that is specific to a particular user.

Cookies can be temporary or permanent. Your browser keeps track of temporary cookies as long as it is running, but deletes them when it is shut down. Temporary cookies are used to pass information between Web pages during a single visit. (Online Banker uses this method.)

Your browser saves permanent cookies as tiny files on your system to maintain settings or data between multiple visits. "Permanent" cookies are actually set to expire at some time in the future (commonly between 30 days and a year from their creation date), and are automatically deleted from your system at that time.

Cookies are currently the only way to save personal choices between visits to a Web page without having to log on each time you come to the page.

Cookie Concerns

Although disabling cookies for your browser is an option, it's intended for a small minority of people with extreme security or privacy concerns. If you choose it, you give up a lot of convenience in exchange for a small amount of perceived privacy.

For example, with or without cookies, it is currently possible for the creators of a Web site you visit to keep track of such things as the following:

The address of the page that contained the link that brought you to their site

All the pages you visit on their site

Choices you made on forms on their site

What browser you are using

Extensions you might have added to your browser

The operating system you are using

The time your system clock is set to

The absolute address (IP address) of the server that connects you to the Internet

The only thing cookies add is the ability to keep track of this type of information over multiple visits, thereby allowing the creators of the Web site to build a more precise profile of a particular visitor's preferences.

But the creators of a Web site do not have access to personal information such as your name or your e-mail address unless you specifically give it to them. Therefore they have no way of matching any data they might have gathered with a specific user.

The only information available to a Web site that comes close to identifying you specifically is the IP address, but most Internet servers provide connections for multiple users, and each user is usually assigned a new IP address randomly each time they log on.