Also, the ability to whitelist an author or book for extra moderation seems like a no-brainer. After there is evidence of harassment then all user content needs to be approved before it is made public. Enable trusted moderators from the community to help with this if paid moderators cannot keep up.
This seems like it could get so so much worse than it currently is. The target of harassment seems to be taking it well but what happens on a platform like this to someone that isn't as prepared to deal with it?