One extra note I'd add. We've had a few events where another group, or a fraction thereof, and our group combined for the event. I'd recommend strongly against these unless you think there is significant demographic overlap, as I felt it strongly diluted the event, both in terms of group feel and also in terms of group focus.
HPMOR wrap-party being a good example of an exception where it worked fairly well... but I'd be curious about your experience with examples that didn't work.
We've been running regular, well-attended Less Wrong meetups in London for a few years now, (and irregular, badly-attended ones for even longer than that). In this time, I'd like to think we've learned a few things about having good conversations, but there are probably plenty of areas where we could make gains. Given the number of Less Wrong meetups around the world, it's worth attempting some sort of meetup cross-pollination. It's possible that we've all been solving each other's problems. It's also good to have a central location to make observations and queries about topics of interest, and it's likely people have such observations and queries on this topic.
So, what have you learned from attending or running Less Wrong meetups? Here are a few questions to get the ball rolling:
If you have other specific questions you'd like answered, you're encouraged to ask them in comments. Any other observations, anecdotes or suggestions on this general topic are also welcome and encouraged.