Astoria futures: offline-enabled data services
We mentioned that we were doing some early thinking of “Astoria Offline” back in Mix 2008, where we even demo’ed an early proof of concept. Now we’ve been working on various design aspects of Data Services for its future versions, and synchronization/offline support is one of them. It’s still an experimental thing with no official home or release vehicle, so this is the best time to follow the design process if you find the scenario interesting, as this is when it’s easiest to influence the direction we’ll go for.
A short way of describing this can be: “imagine you can point Visual Studio to a data service and say ‘take it offline’, and things just happen”.
Of course, the real world is more complicated than that 
Astoria Design Walkthrough: Thinking of a future with sync & offline