Isn't this what ancient local BBSs did? Back in the 90's when in my teens/twenties that was how I found interesting local groups of people/organic raves (i.e. not ones organized by promoters) outside my established circles in Santa Cruz/the bay area. Also some of the most uncomfortable/awkward unsocial/nerdfest social evenings so not everything was a hit.

I'm guessing that there are now Discords that fill this niche?