censorship against spam? plots and terrorist attacks? calls for violence? practicing medicine without a license? child pornography? bigotry? Hate? Lies?
Personally I would punt moderation and labeling to third parties.
let others label the content and then pay people/groups to share they're bulk labels lists. with a mechanism for dispute.
focus on what matters collecting data and selling ads. although a user should be able let specific advertisers sponsor they're content and or buy the content at the advertisers rate.