A mailing list's Policy and Usage Statement describes the general purpose of the mailing list and provides information that mailing list users and moderators need to know in order to use the mailing list effectively. A Policy and Usage Statement is less formal than the organization's Terms and Conditions and Privacy Policy and, is usually written by list administrators rather than legal experts. It can be short and sweet or thorough as desired, but it should answer certain key questions.

Admins enter a Policy and Usage Statement in plain text or HTML format when adding or editing a mailing list. This statement is displayed on the Mailing List Home page.

Mailing lists often serve a diverse set of subscribers—who may live anywhere in the world—and range from inexperienced newbies to those who remember what the world was like before there were personal computers or an Internet. The mailing list's Policy and Usage Statement should address the needs of this diverse group, with particular attention to inexperienced and less technical users. These users may need guidance on proper netiquette almost as much as they need instructions on how to subscribe and unsubscribe.

However brief the Policy and Usage Statement, it should provide answers to these key questions or refer the user to an area of the site where answers are available.

There are three general categories of netiquette transgressors: fools, boors and spammers. Fools include those who are unaware of proper netiquette and require education, as well as those who should know better but need periodic reminders. Most of us fall into this category at times, so list admins tend to respond to foolishness proactively with education and retroactively with reminders.

Boors include those who deliberately and routinely transgress the boundaries of appropriate behavior as well as those who react inappropriately on occasion. Being human, we all have moments when we do not exhibit our best behavior and hope that others will overlook our lapse and see that we are truly well-intentioned. We also realize that what may appear to be boorish behavior on the part of another may simply be a difference in communication style, world view, etc. So some tolerance for perceived boorishness is wise as an unstated policy. On the other hand, if your mailing list intends to enforce consequences for bad behavior, it is necessary to describe the kinds of infractions that will not be tolerated and explicitly state the consequences for crossing this line. This will vary from list to list. Public lists tend to be more tolerant of profanity and advertisements than private lists. Even with consequences explicitly stated, Admins can and should use their discretion regarding enforcement, but having an explicit description of infractions and consequences helps admins explain their decisions when challenged by users whose posts are rejected or who have been unsubscribed and banned from resubscribing.

Spammers frequently target mailing lists as method of distributing unsolicited bulk advertisements, and most mailing lists employ a zero-tolerance policy for spammers: immediately and permanently unsubscribing any user who attempts to post spam. Spam is such an enormous problem that there are global organizations dedicated to identifying spammers and neutralizing them by maintaining lists of the IP addresses of known spammers. Kavi uses lists maintained by Spamhaus, the oldest and best-known of these organizations. The originating IPs of all incoming email are checked and if this IP matches an IP on the list of known spammers (i.e., blocklist), the email is automatically blocked (i.e., deleted). But spammers employ many devices to bypass spam filters and, like viruses and other malware, spam is continually evolving, so the only way to completely block spam from your list is to have all posts moderated.

For more information on spam, including how to manage your list and use list text to guard against any accusation of spamming, see What You Need to Know about Spam.