No "official" set of rules was ever published, because if rules are set in stone, then people will come up with clever ways to bypass them, and then complain when a moderator takes action.
This is so true it's scary. I think it's important to point out that it's even more important to stick to the "spirit" of the rule rather than to the letter of the rule. There will always be a roundabout way to interpret rules that make it such that you're sticking strictly to the letter of the rule, even if you're clearly crossing the boundary. To that end, the rules should also stipulate that someone trying to get around the rules by sticking to them on a literal level while clearly infringing on what the rule was intended to prevent, is also not allowed.