This isn't to detract from what the author has said, but Google Docs does have a public API now. I wanted to mention this because the public API is fairly new,

This isn't to detract from what the author has said, but Google Docs does have a public API now. I wanted to mention this because the public API is fairly new, and people may not know about it. I am not sure if the API is rich enough to achieve what the author is describing though. It's also not built on any kind of standard, like email, or other examples that are described.