Ad rotation is the practice of showing multiple advertisements in a single location on a web page. Ads may be rotated with each new page load, within a single page load, or both. Because the ads are placed in the same location, they are typically the same format.
The goals of ad rotation include:
Ad rotation software, known as ad rotators, commonly provide features such as the following:
Technical implementation
Technically, ad rotation can be accomplished in multiple ways. The three most common approaches are server-side, client-side and service-based.
With server-side ad rotation, the ad is selected on the server and the corresponding HTML markup is generated and then served.
Client-side ad rotation typically involves JavaScript of some sort (either straight client-side JavaScript or else AJAX calls to the server.
Service-based ad rotation is similar to client-side ad rotation in that it typically involves placing a small amount of JavaScript in the web page, but the JavaScript calls against a third-party service that provides its own management interface for specifying ad delivery options. Google's AdSense service is an example of service-based ad rotation.