Way back in early 1990's, before spam was even an issue, degree of subscriber privacy was not a question. With new CAN-SPAM law seriously threatening email marketing it is crucial now more than ever to make subscribers, both new and old, well aware of your dedication as a publisher to abide by their wishes.
Federal Law now makes it a felony to engage in email marketing activities that we have all known are simply unethical, making attention to detail in your spam policy highly important. The new law is rather controversial and poses many problems believed to actually increase spam. However, clearly defining your intentions and willingness to fight against spammers, as well as promising never to spam anyone builds trust and credibility. What's even better is that it lends support and legitimacy to email marketing in fight against new laws.
So, what guidelines should be followed? Although this seems upfront like a no-brainer, it is specific wording that can be tricky.
(1) Stay away from what I call "lawyer talk". What's point if a potential subscriber has to go to library to figure out what you promise to do. Tell them your intentions in simple sentences. There is no need to use fancy wording.
(2) Explicitly state that you strictly prohibit spam. You must spell out your stance for your subscribers. There is no room for interpretation here.
(3) Promise to them that you will never spam. Seems silly to say this but remember point here: credibility, trust, and protection.
(4) State details regarding your publication as to how many mailings they should expect. Keep in mind average person's memory span. Subscribers don't really like surprise mailings.