I think these would help Scratch grow immensely. A friends list: You can click on someone's profile and send them a friend request. If they accept, you'll both appear in each others friend list. With friends, you can set up full colabs, which let the accepted friends edit the same project at once.

Follows already do this pretty well, and the editing the project at the same time thing has been suggested countless times in the past, I think the ST said it was a good idea but it'll be a while before they can even consider it.

This is a rejected suggestion -

The Official List of Rejcted Suggestions wrote:

2.1 Adding users to work on projects
Having multiple Scratchers work on the same project would be difficult to moderate not only due to technological limitations but also because it could lead to private messaging; for more information, see #7.1 on this list. This suggestion includes live editing (similar to Google Docs) and other forms of private collaboration. If you would like to work on a project with another Scratcher, you can remix each others' projects.

At the moment, a turn-based collaboration system for shared projects is NOT rejected. You can discuss it on this topic.