Setting one up isn't that hard. There are a lot of web sites where you can do just that.
The hard part is getting people there to use it.
I've set several up on my own domains, and have had some activity on one of them for a while, but I didn't really keep up with it so it died down (which is what happens to most of them if they manage to get any traffic to begin with). There's a lot of options available. What you should do depends on whether you want to spend any money, and how much time you're willing to spend learning how the systems work.
Feel free to PM me. I can more than likely at least get you started in the right direction, but I need to know more about what you're willing to learn, how much time you have, etc. And what you're end goal is, of course.
_________________
I'm not likely to be around much longer. As before when I first signed up here years ago, I'm finding that after a long hiatus, and after only a few days back on here, I'm spending way too much time here again already. So I'm requesting my account be locked, banned or whatever. It's just time. Until then, well, I dunno...