As far as rules go I believe self-discipline is the key, if I have something to say that is designed to inflame part of the community then I should expect to be publicly slapped down and reprimanded.
If I act illegally I take my own risks, but I would expect the community to point out my actions are not acceptable.
If I want to operate or promote an adult or gambling related website, which are perfectly legal in my jurisdiction, then I should be allowed to do so. I understand that minors will be welcome to join NB, so I also understand that I should keep my language to an appropriate level so that they can still participate without the authorities feeling the need to get involved. But on this point, would it be worthwhile creating extra forums that deal with these niches, or does the community have an opinion about them generally?