Good idea!
Though, note: Some require you to ask for permission to see the list, for reasons of privacy. So there is some conflict between making this knowledge publicly available and the privacy. I'll suggest doing this for DC, though, since ours is public.
Looking at the discussion section recently, it seems like over half of the posts are meetups. I think it's really great that so many LessWrongers are able to get together and do interesting stuff. Looking at a lot of the topics, I often find myself thinking "I wonder what they ended up talking about." I looked at the meetups page and it looks like many give a description of the topic, but there is rarely any public followup. I also did a search which turned up surprisingly few post-meetup posts.
For example, this Los Angeles meetup from a few days ago about resolutions looked really interesting to me and I'm curious to hear what kinds of strategies were proposed and if there were any insights or anecdotes that came up that would be useful to share with those of us that couldn't attend.
I remember reading a meetup report back in November that told the story of the exercises they went through and it seemed to spark some good discussion. It even forced me to make a note to try some things on my own. This one was atypical in that it was very detailed and was a crosspost from a personal blog, but I feel like even short reports would give a chance for the rest of the community to chime in and give praise, suggestions, and feedback.
When I tried to think of reasons not to share what happened in meetups, I came up with a few potential factors: