Almost every developer event is organized around a constituency. A
language, a framework, a platform, a city. That works well when the
subject sits neatly inside one of those boundaries — a talk about a
new C# feature has an obvious home.
The subjects people most want to talk about usually do not. What AI
actually changes about the job. Whether to go independent. What
happens to a career after a layoff. Hiring, burnout, pricing, the
platform nobody's group has claimed yet. These cut across every stack
and every city in the region, which means no existing group is quite
the right host for them. A .NET user group cannot really convene
"what does this mean for our careers" — not because it is a bad
topic, but because it is not a .NET topic, and most of the people who
would want to be in that room are not in that group.
Pop-up Meetups exist for exactly those subjects. The
topic comes first; the event is built around it. There is no fixed
night, no permanent venue, and no particular community it belongs to.
Nothing to join and nothing to have been a member of. If the topic is
interesting to you, you are the intended audience — whatever you
write code in, or whether you write code at all.
That is also the practical reason the format is light. A standing user
group needs a venue, a night, and a speaker pipeline sustained
indefinitely, and when any one of them lapses the group quietly dies.
A Pop-up Meetup needs a topic worth an evening and a room to hold it
in. When those exist, we schedule one and announce it. When they do
not, nothing is failing — there is simply nothing on the calendar.