Ad rotation is the practice of changing the ads displayed on a web site, usually with every new page load, to keep the ads fresh and dynamic so users will continue to pay attention to them. With an ad rotation system in place, owners of a website can sell more advertisements, as they can swap out ads regularly to display new content. They can also charge a premium for their advertising space by moving ads through the premium slots rather than limiting those to a static display ad. Many websites use this technique to deliver ads.
There are several ways a website owner can display ads. One option is to work with a third party client that displays ads; the website owner does not have ultimate control over the display, although he can usually rule out certain kinds of content that won't fit with the style or tone of his site. Third party advertising companies often use ad rotation to move ads through. The website owner installs a module that looks up ads on a server and displays them as users load pages.
It is also possible to host ads directly on a site's server. If the website owner wants to use ad rotation, she will need to install a program to do this. Javascript is commonly used, as it is simple, flexible, and powerful. The script can be set to refresh the ad every time the page loads. As users reload the home page or move through the site, the ads on the site will change.
One advantage to rotating ads is the ability to target advertisements. The ad rotation script can target ads at a particular demographic. In email, for instance, someone writing a friend about a floral delivery would see ads for florists and delivery services. Conversely, people having a conversation about a book club might get ads for bookstores and book-of-the-month clubs. The ads tailor themselves to the content on the page and the expressed interests of the user to make them more relevant.
Internet advertisers can pay for their ads by impression, in bulk rates, or in other ways. They usually want evidence that their funds will be efficiently spent. Some may expect ad rotation to ensure that their ads are seen by as many browsers as possible. They may structure terms and conditions into the contract, like a mandate that their ads appear a certain percentage of the time.