- The primary purpose of a cookie is to identify you to the website that placed the cookie on your computer. The cookie contains a text string that your browser sends back to that website when you visit it again. The website recognizes the text string and displays a customized version of the requested page for you.
- On its own, the HTML coding used for most websites does not have the ability to save and recall your preferences. Many websites give you the ability to change certain aspects of the way pages are displayed such as the font size and background color. Cookies make it possible for those settings to persist when you visit a website later. In addition, cookies may reduce the number of times that you have to enter your username and password when viewing certain websites.
- Many people have concerns about the privacy implications of browser cookies. A cookie does not contain any personal information about you -- it identifies your Web browser, not you. However, some advertising companies use cookies to track the websites that people visit and what advertisements they click while browsing. Google does this with its AdSense network. Although advertisers cannot use this information to determine your identity, it is used to display advertisements that you are statistically likely to be interested in. All websites that display AdSense advertisements are required to display a "Privacy Policy" link that you can click to learn about cookies and how they are used. Many other advertising networks also require this.
- You can adjust your Web browser settings to prevent cookies from being saved on your computer. In Internet Explorer 9, click the gear-shaped button in the upper-right corner of the screen, and then click "Internet Options." Click the "Privacy" tab, and then click "Advanced." Click the "Override automatic cookie handling" check box, and then click both "Block" radio buttons. Disabling browser cookies can help prevent advertising networks from tracking your activities online. However, it can also prevent many websites from working properly. In addition, if you may any display changes when viewing a website, you may need to make those changes again the next time you visit.