Olhando para o Gerenciando pools de aplicativos no IIS 7 Página da TechNet, é simplesmente separar os aplicativos uns dos outros. Aqui está o bit relevante.
An application pool is a group of one or more URLs that are served by a worker process or a set of worker processes. Application pools set boundaries for the applications they contain, which means that any applications that are running outside a given application pool cannot affect the applications in the application pool.
Application pools offer the following benefits:
Improved server and application performance. You can assign resource-intensive applications to their own application pools so that the performance of other applications does not decrease.
Improved application availability. If an application in one application pool fails, applications in other application pools are not affected.
- Improved security. By isolating applications, you reduce the chance that one application will access the resources of another application.