I don't think an open community would work very well. The signal::noise ratio for each individual would be very high and they would have no social obligation to follow up with eachother. It seems no different than posting the latest update to Facebook / a blog / HN / Product Hunt.

My two cents is to find driven people you already know and get a small group (5-10) together to do this.

YC does this by subdividing its now larger batches into different groups that meet together with their mentors every two weeks. On my own, I created a slack channel with about 10 other U of I founders. We can all commiserate about our startups, help eachother out with intros, and share good news and progress. Its more meaningful as well due to the shared friendships and history.

PS: If you're an Illini founder hit me up to join our slack. :)