Following up on my previous post - the  reference application is now called PSO (Product Support Online). It will be developed in two phases to align features better with the changing nature of Azure and SDS APIs, but more importantly, to draw a clear line between on-premise applications and cloud-based applications so developers consuming the corresponding guidance would undestand how difficult (or how easy, I hope) it is to move this kind of application to Azure Services Platform.

High-level architecture diagrams for both phases are shown below. As you can see, Phase I is a pretty typical web application adding Silverlight UI and Live ID delegated authentication to the mix. The idea here is to isolate all operations with data to a separate data access layer (DAL) which can later be switched from SQL Server to SDS just by changing a connection string (this is promised by the SDS team and will be delivered sometime in the end of May 2009 in invitation-only SDK and in June-July 2009 in a public CTP).

Phase II is all about the cloud. It will add integration with Access Control Service so claims based federated security can be utilized by tenants of the application:

The most interesting part here is, of course, Task Engine, but it deserves a separate topic; the only thing I can disclose at this moment is that it's supposed to be flexible enough to cover many more scenarios than product support and feedback.