A 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. The advertisement known as a "click through." In many cases, banners are delivered by a central ad server.

Web banners function the same way as traditional advertisements are intended to function: notifying consumers of the product or service and presenting . Web banners differ in that the results for advertisement campaigns may be monitored real-time and may be targeted to the viewer's interests. Behavior is often tracked through the use of a click tag.