It is a requirement that if you’re a member of the community, and one day you stop showing up, people will come looking for you to see where you went.I think there's a lot of truth to that. A community is more than simply a gathering of people in the same place. It is more than a lecture hall, more than a tutoring center. For you to belong to a community, your leaving must affect it.
So if you want a community in your user group, you need to think beyond putting people in a room and having them learn. You need to pull them in, and connect them to others.
To be a good community facilitator, then, you need to know enough about your members to know who would gain a lot from knowing each other - that's the networking component - but then also who would just get along really well. Of course at the same time you're introducing some members, the rest will hopefully be socializing on their own. All this is core to your group even if no one discusses a word about technology.
Finally, don't forget about your new members! A meeting of old friends is great but it can lead to newbies feeling left out or unwelcome. Best is to ask some of your longer-term members to help you make sure no one leaves without a personal welcome. That way your community will grow and you'll also build other leaders.
(P.S. The quote is from an old blog entry by Adam Fields complaining about the lack of connection between users on many websites. But of course real-world groups can suffer from the same problem, if we aren't careful - and I think it's even more deadly.)