Private Storage for Web Aps

Web Aps like Gmail and Flickr are great. I love them and use them for most of what I actually do these days. Google's mail application has become my main connection to people in my professional and personal life. What would happen if Google decided to lock me out of my account? That is a problem that might just require another private service.

It would be a way to store your email messages, photos, and documents created with web aps. I don't know exactly how this would work. It might take the form of an automatic backup system. It might use the application APIs to mimic the functionality, but actually create content that isn't stored on Google or Yahoo servers.