Most of dang's comments (that I've came across at least) are moderation actions, like telling people how they're not following the guidelines and so on. But yeah, also the actual backend moderation actions should obviously be included in the training set.
Excellent at producing a specific outcome (optimizing for certain variables) - whether that specific goal of an outcome is anywhere near optimal in a comprehensive sense is another matter entirely.
Excellent at allowing the same 10 guys (and their alts) to dominate almost every discussion. For truly serious topics, this place isn't all that different. Manipulation is a powerful weapon.
Metafilter also seems to work fine. Just charge money for each account creation, eventually the repeat trolls will get tired of paying over and over again.
Of course, dang based moderation also works well but you need a dang for that.