I've tried using a Wiki but it's just not worth the extra time to setup, teach others, and maintain.
Comments seem to be the most effective for collaboration on Graal, resorting only to txt files when the information is sensitive enough. I usually use.. *projects, *<project> and *<project>_assignments
All communication through RC, I don't want to be annoyed over my messengers because what I do on Graal. If they can't log on RC or Graal, then they probably can't work (or don't want to) either.
A simple Gantt chart add-on for RC would work great for project management though.