This is especially important, adds Jefferson, when companies use a shared mail server or host a website on shared hosting. "If you are [doing so], and one of your 'neighbors' spams, you can end up listed," she points out. "It stinks, but if you share the same IP with a spammer, IP-based blocklists have the unpalatable choice of listing the IP, and thereby blocking innocent bystanders as well as the spammer(s), or not listing the IP and letting the spammer spam away."

5. Piss off your technically knowledgeable staff.

If someone is on the inside, and they have been nodding along at each of the points I've already made, it's not all that difficult for them to get a company blacklisted. (I'll avoid examples here, because I don't want to make the job too easy for any disgruntled employees who might be reading this article.)

I'm sure that you treat all your employees well, that they are qualified for their jobs and that you have trained them on acceptable use policies for e-mail (you do have them, don't you? Please tell me you do). Yes, sure you treat every employee with unrelenting positive regard and gobs of respect—and I am the Queen of the May.

Someone, somewhere in your organization will eventually decide that he is being pushed to the limit—and then you'll end up in a situation like the City of San Francisco's rogue network administrator. What technology do you have in place to make it difficult (it'll never be impossible) for an upset insider to give his manager a Very Bad Day?

6. Run a sloppy mail server.

Mail servers that don't follow the rules have a myriad of ways to get their feet caught in a spam-trap, some of which were enumerated in other CIO.com articles. Some of them are technical, under the purview of your e-mail admin, such as "The HELO/EHLO string should ideally match the full domain name."

Bottom line, here: follow the standards.

For more down-and-dirty details, see An Introduction to E-mail Management, An Introduction to E-mail Technology and Getting Clueful: Five Things You Should Know About Fighting Spam.

7. Ignore the security on devices which may be compromised by spambots.

Your e-mail server may be pristine in its behavior, but if one of your end-user's computers has been taken over by a virus which is sending spam, your domain is still responsible for polluting the Internet. Pay attention to software installed on your desktops and servers, either by staff (using social engineering or deliberate malfeasance) or when users visit compromised websites.