ad server

A third-party system composed of powerful server hardware, ad serving software, and a powerful internet connection, used by advertisers and web publishers for rapid and reliable display of online advertisements. An important component of ad servers is independent tracking of ad display and click information. Many ad networks, including Burst and Fastclick, offer separately licensed versions of their own ad servers which may be used by web publishers who manage some or all of their own advertising sales rather than outsourcing to ad networks.