I'm trying to launch a new campaign and need to contact players who sign up to coordinate the schedule. There's currently no way to do this from within the app, but with some URL hacking, I can presumably get to the players' community profile and message them on there. I did a quick search and found the following thread, which indicates that more messaging features are on tap for the app:
<a href="http://community.roll20.net/discussion/2132/getting-from-app-roll20-netusers-to-community-roll20-netprofile-/p1" rel="nofollow">http://community.roll20.net/discussion/2132/getting-from-app-roll20-netusers-to-community-roll20-netprofile-/p1</a>
So in addition to +1'ing this idea, I'd like to suggest that you just couple the two separate applications. If there's forum message and app messaging, then people are going to split the discussion. And that's almost as bad as crossing the streams.