Web banner or banner ad is a form of advertising on the World Wide Web delivered by an ad server. This form of online advertising entails embedding an advertisement into a web page. It is intended to attract traffic to a website by linking to the website of the advertiser.These images are usually placed on web pages that have interesting content, such as a newspaper article or an opinion piece. Affiliates earn money usually on a CPC (cost per click) basis. For every unique user click on the ad, the affiliate earns money.