I opened the session by defining the three Cs that I thought were key to framing our discussions about online communities:
Community, Communication and Commitment.
In simple terms, a COMMUNITY is just people + a shared interest - whether that be scicomm, the safety of your neighbourhood or having input into your kids' schooling.
With good COMMUNICATION, a sense of belonging develops. Communication is used to reinforce the norms and values for the community - the things they share interest in, the accepted behaviours. Sense of belonging is an indicator of a healthy community, but it is not the sole goal of community building.
The sense of belonging means you start to think about what problems you could tackle together, how to DO STUFF.
Where it looks like there's a path to achieving those things - reinforced by more good communication - then a COMMITMENT to the community occurs.