Social media where you "speak with" sounds fantastic, but how you would do it Slack/IRC is one way do it, those have usually tightly knitted community but there is definitely other more creative ways do that.
So to create social media that lends itself this direction, take the focus away from individual expression in a bubble and put the focus on topics, just like Slack/IRC/forums/BBSes do/did.
Google+ was actually a step in this direction and was the home to a number of topic-focused communities as a result, but Google wasn't prepared to follow through. Maybe someone else will.