Sharing Rights

I think a good idea would be to have three (or more...) different sharing licenses. As the author, you can share just so the other can read, so that they can only edit, so that they can edit and write, and... I don't know, can you think of something else? Give up primary authorship, perhaps?
Along with this, it would be awesome if documents that have been edited were marked somehow. So that you knew what has been worked on by your fellows. Within the document, what has been changed could be hilighted somehow (perhaps a big colorful { mark to the side or something)
Also with this sharing system, it would be great if you could have one or more names associated with a document... The name for a document that only you see and the one that everyone sees. That way, you can organize your own box to your own taste without infringing on how others do. However, you do have folders, so this is not a problem here as it is with other systems which I have used....
scaeascae