Yeah, I think we are already seeing this with private messaging groups, matrix, discord etc. Could be based on interest or local community, friendship groups. I think a message board revival would be amazing too. These places don't even really need to be private, the barrier of entry is having an interest in the topic and staying on-topic. ¯⁠\⁠_⁠(⁠ツ⁠)⁠_⁠/⁠¯