I reckon the trick in working out moderation policy is to look at the motivation behind what people post. That's what it's all about.
Running a forum myself I find it easy to work out what the motivation is. On my own forum I don't have any difficulty in figuring out who the spammers are or who is just dropping a link. I have a couple of tricks in place - one of which is asking new members to say where they are from. Spammers almost always get that one wrong.
It's all about motivation. Much of the moderation concern might be about people with good motivation being treated like criminals. It's always seemed daft to me as it's easy to get around the problem by looking about the motivation of the post.