That happens because these placed only attract extremes and let them stay among themselves. The key to a platform that does not become a cesspool is to disallow

That happens because these placed only attract extremes and let them stay among themselves. The key to a platform that does not become a cesspool is to disallow isolation and bubble building for extreme oppinions. Yet, this bubble building is what people desire and the only way to create a successful social online service is to cater to that group building. Real life rarely provides similar comforting bubbles of likeminded and reaffirming people. You still need to interact with other people even if you disagree with their views. In front of your computer screen, the right forum for sharing your views is just a few button pressed away. It is too easy to avoid the rest. To play devil's advocate and take an extreme position for the sake of discussion: we don't more free speech. Instead, we need a to introduce a duty to listen that goes both ways: if you want to express your opinions, you must also listen to what others have to say and especially, how others respond to what you say. And you do not get to pick and choose who you listen to. In essence, nobody must ever have full and exclusive control over the shape of the community they are part of.