@amerika how would you ensure rigorous speech that is open to all? wouldn't you be more restrictive than twitter who allows trivial, irrelevent and uninformative speech as long as it's not 'hateful'?
'hate speech' is replaced by 'lazy speech'
i would agree that this would be useful for a debating platform, but a social network im not so sure.
My take on it, having fought this out in a number of forums, is:
1. Avoid viewpoint discrimination
2. Appoint quality censorship
That is, someone can express any opinion, but in the right form.
That means that you can post critique of $ethnic_group $religious_group $sex $sexual_preference etc but it has to fit the right form for reasoned, useful, relevant, insightful, informative, and topical discourse.