Web sites use cookies for several different reasons:

• To collect demographic information about who is visiting the Web site. Sites often use this information to track how often visitors come to the site and how long they remain on the site.
• To personalize the user's experience on the Web site. Cookies can help store personal information about you so that when you return to the site you have a more personalized experience. If you have ever returned to a site and have seen your name mysteriously appear on the screen, it is because on a previous visit you gave your name to the site and it was stored in a cookie so that when you returned you would be greeted with a personal message. A good example of this is the way some online shopping sites will make recommendations to you based on previous purchases. The server keeps track of what you purchase and what items you search for and stores that information in cookies.
• To monitor advertisements. Web sites will often use cookies to keep track of what ads it lets you see and how often you see ads.