Deploying ASP.NET AJAX applications is not too complex, but there are some pitfalls to be avoided. Configuration errors are the most common complaint. This is made worse by the fact that development environments are often different from the production environment, and configuration changes are a necessary part of deployment. Before beginning deployment, you should check for a set of common issues that cause problems and can be difficult to track down and are also easily avoided.
The Web Deployment Project add-in for Visual Web Developer can help in automating a reusable process for moving from development into production. It allows for extensive customization for your unique environment and makes it easy to establish an environment where designers and developers collaborate to produce the application and then automated processes are employed to move it into production reliably.
For single applications that deploy to a cluster of web servers, there are additional configuration concerns. Machine keys need to be synchronized and you may need to use a backend database to store Session state.