It might depend on the community, then. In my area, the big social media outfits are not useful in that way at all. (Except for selling stuff on Facebook, but that's not what I was talking about.)
Facebook and Reddit are the only ones I'm familiar with for this, though, and they both have the same problem -- they are dominated by a very small number of people.
Always. But maybe a factor is the size of the "community"? A hub city has X number of residents plus Y folks who work there plus Z folks who live in suburbs but are counted as part of the metropolis.
OTOH a small city is small, so the folks may share more in common -- and thus push out interlopers and ignore noise makers.
I live in a small city. I think the reason that social media hasn't really become central for community here is because we have a small free arts & entertainment newspaper that has served the role for longer than I've been alive. That's where everyone expects to find public announcements, events, buying/selling things, etc.
Craigslist is also very popular here. Does that count as social media?
Facebook and Reddit are the only ones I'm familiar with for this, though, and they both have the same problem -- they are dominated by a very small number of people.