In this chapter, we learned the basics of AJAX development using the Microsoft ASP.NET AJAX Framework and discussed the performance, responsiveness, and architecture benefits of an AJAX application. We learned how to separate the server logic into a service-oriented API that can be shared between multiple components and how to build feeds within the site context. We learned how to build and deploy AJAX components within Web Parts as well as the design challenges associated with script components instantiated from Web Parts. Finally, we looked at the SharePoint AJAX Toolkit and how to leverage common architecture components to build and deploy lightweight AJAX controls. In the following chapters we will learn about lists and content in the WSS platform that can be further exposed to AJAX-enabled XML APIs.