I was poking around today and found this great article on caching: http://www.cloudcomputingdevelopment.net/cache-management-with-windows-azure/
Caching is a great way to boost application performance and keep down overhead on a database or file system. Its also great when you have say 3 web roles as shown in this articles Figure 2 that can share the same cache. If one of the roles goes offline then the cache is still there and can be used.
You can change out your asp.net caching to use this pretty easy. Its pretty cool.
There’s a sample that’s mentioned in the article that shows how to use this. You can download the cache here.