There was an MIT startup, Permabit, that tried to make a cloud based storage system which backed your own local disk. One idea was that your local storage is faster so you should use it for local things, and offline computation, but that if a shadow copy was being backed to the cloud in encrypted fashion. If your local storage fails, you just replace it, and the data dribbles back in from the cloud to your new local device.
They also had some hack whereby large common files (like app executables) where compressed using their hash code or something, but that is not the important idea in my opinion.
I think having that transparent local/cloud duality is one piece of the puzzle for a service which is both fast and local and also cloud based. You shouldn't have to care where your data lives. The other pieces of the puzzle are how to grant fine grained shared access without confusing users and introducing security holes.
They also had some hack whereby large common files (like app executables) where compressed using their hash code or something, but that is not the important idea in my opinion.
I think having that transparent local/cloud duality is one piece of the puzzle for a service which is both fast and local and also cloud based. You shouldn't have to care where your data lives. The other pieces of the puzzle are how to grant fine grained shared access without confusing users and introducing security holes.