True, there isn’t any in-site messaging (yet?). Right now, this forum is the ‘best’ place to get in touch with others. It’s not a great solution, since it requires others to be present here as well.
A while ago, I added Planned Runs (request a run) to the Ideas category. It didn’t get any traction at all. 
I’ve also thought about embedding the forum into the site, but haven’t had time to write anything up for that.