I think this overlooks the biggest issue. It's not just that Twitter (and most online forums) aren't representative of the public at large. It's that these sites are driven by a tiny number of hyper-online turbo posters, many of whom are likely mentally unwell. It's worth reading this post: "Most of What You Read on the Internet is Written by Insane People"[1].<p>Even that, I believe, understates the problem, because I think these hyper-online folk are more likely than the average person to be active in multiple internet communities. I've been surprised to find a personality on small niche game forums pop up as well known Twitter political commentator, or read a comment on Hacker News, switch over to a niche Reddit sub about an unrelated topic, and see comments by the exact same user (same screen name and beliefs).<p>The other day I passed a crazy person on the street who had mountains of handwritten cardboard signs plastered all over a park. We can easily tell someone like that is crazy. But if they plaster their screed all over the internet in bit sized posts and Tweets, and none of them are _too_ obviously insane, it's easy to think this is just a normal person. And since almost no online site has posting limits, crazy people that spam messages online all day are simply going to drown out any normal people on the platform (with the upvoting systems only exacerbating these problems).<p><a href="https://www.reddit.com/r/slatestarcodex/comments/9rvroo/most_of_what_you_read_on_the_internet_is_written/" rel="nofollow">https://www.reddit.com/r/slatestarcodex/comments/9rvroo/most...</a>