I'm Andy Warren, currently a SQL Server trainer with End to End Training. Over the past few years I've been a developer, DBA, and IT Director. I was one of the original founders of SQLServerCentral.com and helped grow that community from zero to about 300k members before deciding to move on to other ventures.
We had a visitor from another group at our recent www.opass.org meeting and it was interesting that one bit of feedback was because we had filled every seat the visitor felt it made for a better experience because people talked more to each other - due to sheer proximity, where at other meetings with lots more space people tended to spread out and therefore not talk as much. That makes sense, but does that mean user groups should seek smaller venues and just deal with overflow if it happens? Or can we manage to get us to sit together in spite of our reluctance to sit close to others unless we have to? No answers here, yet anyway.