> What would be really cool is to have an Emacs buffer that can be edited by multiple people. Then pair programming can be done within the editor. Is there such thing?
Rudel is nice for working on a single document, but tmux is much nicer for pair programming since it synchronizes the whole screen rather than buffer by buffer. That way you don't have to talk through "OK, I'm switching over to this other file now". Plus it works with things like shells and repls. So I'd use Rudel more in a collaborative note-taking context than a programming one.
As always with Emacs, been there, coded that:
http://www.emacswiki.org/emacs/Rudel