You can always moderate by attaching tags to posts, and allow viewers to choose which tags they don't want to see. You can even have per-moderator tags. E.g. m

You can always moderate by attaching tags to posts, and allow viewers to choose which tags they don't want to see. You can even have per-moderator tags. E.g. mod123:spam. And then let user filter by tag wildcard or something similar: *:spam.