These items are used to deliver advertising that is more relevant to you and your interests. They may also be used to limit the number of times you see an advertisement and measure the effectiveness of advertising campaigns. Advertising networks usually place them with the website operator's permission.

These items allow the website to remember choices you make (such as your user name, language, or the region you are in) and provide enhanced, more personal features. For example, a website may provide you with local weather reports or traffic news by storing data about your current location.