"Cursors" was the question; with TMUX and VIM in rogue mode multiple people can type independently in a separate "window." But it only supports one cursor per window.

google docs on the other hand seems to allow multiple cursors on the same window. So one person may type in section 1; while the other person type in section 2 without interfering with each other.

With a single cursor however; when two people type at the same time they almost necessarily interfere with each other. Unless one stops driving while the other types.

I think to implement the 'google docs' style multiple editors would require a different buffer for each user and a merge script that periodically runs the commands for each ofthe other multi-user buffers into each other buffer of the multi-user sessions.