Following the previous point, we started using this idea of a root/collection document for organizing information in Groups as well. Both Groups and Accounts now have such documents, which serve as an entrypoint for the general public to discover and navigate the published information.
The problem with those documents is that they can "escape" from their context, and lose their meaning and purpose. One way or another someone might receive such a root document without discovering the relationship between its de-facto parent (Account or Group), and there's no way for the user to know what they are missing.
Imagine Alice linking the root document (R) from some group (G) inside of her own totally separate document (D). Because you are subscribed to Alice you receive D, you follow the links and discover R, but you don't discover the inherent relationship between R and G, which is a problem, because looking at R without knowing about G is not very useful. You might find out about G, if Alice linked the document including the group's variant, but it's very easy to screw it up, and currently our "Copy Link" button doesn't always behave the way we want.