Vulgarity in the rule book.
The PG13 rule is loosely used as a guideline to what is/isn't acceptable when determining whether a comment is vulgar. The theory is that if society has deemed it appropriate for a 13 year old to hear, it is unlikely that it will be offensive to the majority of Users.
Otherwise, profanity (as explained above) is unacceptable on the stock boards, even when punctuation characters are used to "fill in the blanks" or letters are changed (f**k, azzh*le, etc.). Note that there are also "polite versions" for many acronyms and these are assumed to be the case when in doubt (i.e. "wtf?" = "what the freak?" in the polite version).
I simply asked for civility as there is a Lady present and someone has stopped using the polite versions. Ie: POS or BS.