All the rest as @janitor says, drive will be a local representation of a global filesystem. there will be a drive root for your personal private data, another for public data (others can read) and eventually shared data, the latter being further out after the initial dev bundles (1 2 & 3). Shared is a difficult issue, there are a few ways to do it, but we are pushing it slightly out for now. We have a mechanism which is github like and can resolve conflicts, but requires apps recognise this conflict resolution. So for the time being any app will work on drive as you would expect (well when drive is coded up properly) and for private shared, then we will see changes.