let everyone rate content on multiple relevant criteria. Eg, quality, grammar, agreement, sexuality, violence, hate, etc.
Make some default filters that choose societally acceptable settings for each filter, and hides new content that is unrated.
Enable individuals to tweak the filters to any setting they wish, for a totally custom view, including viewing unrated content.
Enable individuals to share their filters with others.
Voila! A system that allows any content to be posted, but shows only "safe" content by default and allows individuals to bypass the filters if they wish.