These are the rules.
The rules are subject to change, but you are always advised to follow the current set of rules. They are not all of the rules. They are some of the rules. The absence in this list of a particular rule does not mean you don’t have to follow it, if indeed it is a rule. These are intended to be a simple set of general rules for dealing with the kinds of interactions that are prevalent on the internet (web/email). Some of them also apply to the telephone. Use of the rules is at your own risk (as is use of the internet).
But you do have to follow these, even if you’ve lost your rulebook under the stack of AOL CDs. Remember, there are lots of people out there trying to scam you. Don’t make it easier for them. These rules derive from the core principles of “don’t execute untrusted code” and “verify your contacts”.