A banner ad is a simple image file that is served onto a web page. Static banner ads typically consist of a single image file with no audio, video or additional features. The phrase “banner ad” originally referred to a specific size and dimensions for an ad space on HotWired, the first web-based magazine.
These dimensions fit the standard computer screen at the time and were large enough for readers to see without scrolling. The format soon became popular and was adopted by other websites. While standard banner ads are still commonly used, other forms of display advertising may be preferable for optimizing click-through rate and making the best use of costly ad space. For example, rich media banners include features such as audio, video and animation, making them more eye-catching and interactive.
Similarly, expanding banners take up more screen real estate and can be designed to expand when hovered over or clicked on. Ultimately, the right choice of banner ad depends on the goals of the advertiser and the target audience.