I used to run a 2600 meeting, and attended and helped organize LUGs and PUGs. Here's my experience:

- At first, when a new meeting starts, very few people will show up, for at least a few months. If people like it they will keep coming, and slowly ranks will increase. After a while word of mouth will bring more people.

- You need to advertise it a lot of places, not just one website. Wherever your audience might go (out in the world, or online), go advertise there. This doesn't have to cost much money. I literally printed out flyers and posted them up everywhere near where my meetings would be. This brought in people. A local meeting is about connecting with local people, in person, so go places where people go in person. But also some people rarely leave the couch...

- It's very important to show continuous evidence that stuff is still happening, people are attending. Post a weekly/monthly update on a website, with some idea of what went on. Post pictures if you have them. If you really want to post on tiktok, IG, youtube, etc, you can, but it's not necessary; literally any place (that is accessible to everyone - i.e. a simple blog) that shows things are happening is enough.

- Let go of the idea of using some whizbang tech to keep people apprised of what's going on. Local meetings are about one thing: showing up and talking. Forget the mailing lists, rss feeds, bookmarklets, etc. Just post a status update on a free blog somewhere. Show up every week/month/whatever. That's enough to encourage people to attend.

- For organizers: Make it easy to find the event and the people. When people can't find it, and then post somewhere about how nobody was there, that can make it seem like the meeting is dead.

- Reputation is important. If your site lets anyone organize a meeting, but the organizer fails to come through and keep it going, and people show up and find nobody there, word will get around that those meetings aren't serious, and new people won't try to attend. The way 2600 did it worked well: you organize your own meeting, show evidence that you're consistently with it, and after a while the magazine would list you as an official meetup.

- The 2600 route was often literally just hanging out in a mall food court. The LUG route was usually a business/school/etc that would sponsor the group, giving them a place to hang out, sometimes even catering cold sandwiches and chips/soda. I'd let users figure it out themselves, but a guide on how to set up a meeting would help them.

- Having a chatroom (we used IRC back in the day) is fine, but it's not a replacement for the local meeting, and often ends up being an entirely different "thing". It can scare some people away, and can create a weird atmosphere. I would be wary of officially tying them together.

- You would do well to include explicit verbiage about how inappropriate behavior will not be tolerated, that all are welcome, have a zero tolerance policy about harassment and discrimination, etc. This helps the organizer, as it can be difficult to address inappropriate behavior without an explicit policy to point at. It also helps the maintainer of this list, as you can remove meetings if you hear complaints and the organizers don't nip it in the bud.

Organizing is a lot of work, usually unappreciated. Good luck to those who want to take that on!