Relevant question, thanks!
1) Our public meetups attract 15-30 people, varying with the theme. Sometimes there are a lot of newbies/random people.
2) We currently have 83 members, our growth seems likely to continue at ~20ppl/quarter but we expect only 20-50% to become regulars and only around 10-30% to become actively involved beyond attending a meetup here and there. We currently don’t have data on how many people really stay around for more than a year—we have now introduced an annual member status renewal.
3) As we will run our first advanced workshop next week, this number is currently at 15 only (people actively involved whom we know have the knowledge already). We expect it to go up 2-4 fold until the end of this year and then grow more linearly.
4) We have:
1 public and 1 non-public themed social each month
During semesters, monthly intro and advanced workshops
One of our student groups has weekly meetups during semesters and runs an intro seminar
We aim for monthly discussion dinners, this is less fixed though
We meet monthly with our self-improvement group and have bi-weekly open individual debugging/training/planning/gettingshitdone sessions
1-on-1s are usually at around 1-3/week per FTE, but there are weeks with double that in Fall and Spring
Sub-communities and working groups have had similar monthly rhythms so far (hard to say because we only properly started those in May)
We seem to have a co-organised introductory event once a quarter