You could just as well be describing a bulletin board in a physical space, like a community center. Or even an SMS/WhatsApp group.

The problems you're describing are endemic to social spaces and won't be resolved by removing _one_ social space.

This is a horseshit reply that tries to counter an observation about how something actually works with a contrived hypothetical about how something else could work in theory. It ignores the impact of how a medium is organized on the messaging that goes through that medium.

All systems meet that description. You should see radio broadcasting.