First things first: it's Meetup dot com. It's a commercial product owned by a commercial entity. It's not a community service.
Second, nothing replaced it, at least not in the Bay Area for tech meetups. It had a few shaky years under erratic WeWork ownership, and then COVID dealt it a killing blow.
I really think people used to go to Meetup events to catch up with acquaintances and eat the free pizza. They were like low-pressure parties where you could talk to strangers about something you cared about. Most Meetup groups that went to Zoom had huge drops in attendance, because being on a call with strangers is awkward, puts everyone on the spot, and is generally not fun at all.
I think IRL tech meetups can still come back, but I think a lot fewer companies are willing to host. I've spoken to several organizers of small tech enthusiast groups that I care about; they absolutely hate the online format and are desperately searching for IRL options. I go to an IRL AI/ML event that moves around startup offices in SF; they have overwhelming interest and have to turn away 2/3 of the people that sign up, because they just don't have the capacity.
What's left on Meetup:
- dead groups that stopped scheduling events years ago
- groups that are managed by tech companies (in spaces like Web3) that organize events that sound general-interest, but are actually promoting their own services and solutions, and usually fold after 1-2 events
- non-sponsored tech enthusiast groups that run events on Zoom and get like 3-4 attendees per event
My takeaway is that online-only is absolute poison for organizing events where people can meet each other, and IRL is heavily blocked on companies willing to host events and feed people free pizza. All the IRL stuff I've been to this year has been attended and overattended, but there just aren't as many events compared to 5 years ago.