Based on the Refactor revisions to use a version control system proposal changed, I post this proposal.
The problem
Core only allows the first user that sumbit the node form to save the changes; so the others have to see the saved node again and manually make the changes, hoping no other user save it before he does it. Clearly, it's a really slow way to make a contributed document.
In 2006's edition of Google Summer of code a student made collaborative_editor module, giving this facility. But I think it's not so good managing revisions.
During this Summer of Code, I want to make the simultaneous editing better, using the better tool I found in my research. The initial list of posibilities to handle the changes include: some VCS, COMET, AJAX(used in the module).
Why?
Drupal is growing up and it is being used to different kind of websites, but it's not widely used by wikis. So it is a potentially new group of users who can make grow up Drupal still more.
Simultaneous editing improve user interaction inside a web, which is a notably a usability feature, which is one of the planned improvements goals in Drupal 7.
Reactivate the life of the collaborative_editor module developed on GSOC 2006, that actually has no activity.