The reason why moderation exists on sites like Twitter / Facebook is due to: 1. Laws (e.g. child porn, abuse, harassment, illegal speech like Tiananmen square in China). 2. Advertisers - the real customers. 3. Public opinion
In that order, with a pretty big gap between #2 and #3. Don't comply with laws? Out of business tomorrow. Don't do what advertisers want? Out of business this year. Don't do what the general public wants? Maybe out of business in a few years, maybe not, it depends.
The methods proposed in this post are great for dealing with issues around public opinion, but do very little to appease governments or advertisers.