Anonup is raising interesting issues about social media for me. It appears to be remarkable well "weeded" of trolls and bots. The audience is high level, loving, and erudite. There's none of the anger of Gab or idiocy of Twatter.
I post some things to Gab because I don't feel they do much for people here (e.g. article links with a pull quote). Some stuff like my photos it would be nice to have a mechanism to push to both. Anonup is like your peers and bosses are watching, so you had better put out quality stuff.
The one downside I see of a niche social media platform is you don't so easily get to promote people and content from obscurity as a "big name". Once I had 100k+ followers on Twatter I could magically direct attention to videos etc. For someone who had sung a special song, say, and put it on YouTube those thousand views would make their day and week.
Sometimes quality and quantity are in tension; other times not. One public square, or many?
Valid points - but with that said - I think only one public square will most likely have like minded people engaging with like minded ideas - multiple platforms with no censoring would be best if possible IMHO- this would allow all of us to try to understand the why of how so many people can think differently -