Ad rotation
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:
- Allow publishing sites to serve ads for multiple advertisers.
- Keep advertising "fresh". If the ad never changes, users are more likely to ignore it.
- For content-rich sites, increase exposure to advertising by showing multiple ads per page load instead of just one.
Ad rotation software, known as ad rotators, commonly provide features such as the following:
- image management
- display weighting to control the frequency and duration of individual ads
- reporting, allowing advertisers to see how often ads were displayed and clicked
- for service-based ad rotation, management features such as color selection, filtering competitor ads, channel selection (content, video, search, etc.) and payment management
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.