Checking Email Content with SpamAssassin

Initially created by Justin Mason in 2001, the open-source SpamAssassin spam filter is pretty widely used. It's not in use directly at the top tier of ISPs like Yahoo, Hotmail and Gmail, but it does seem to be used by various second and third tier providers, B2B sites, hobbyists and educational institutions. And even though this filter isn't exactly the same as the filters in use at, say, Gmail, there's likely some truth to the theory that "what SpamAssassin suggests may be spammy, other filters may find spammy as well." Great minds think alike, to some degree, the theory goes. Thus, some folks find SpamAssassin to be a valuable tool to check to get some idea if their email messages might be considered spammy.

Want to check your email against SpamAssassin? Postmark has this tool where you can copy-and-paste your message headers and content, or use an API call, to check a message against the SpamAssassin filter. will give you an address to send an email message to, and then allows you to click through to see the scoring results. is another tool that works similarly.

10 Simple List-Building Tips

Here are ten simple list building tests that I keep in my pocket, to share with folks when they ask. Some are better than others, but most of them are easy, no-brainer things that anybody running a site trying to build a list of subscribers should be doing.

Making it Easy to Unsubscribe (#2)

Back in my e-commerce days, we used to use this "one weird trick" to help reduce spam complaint rates: We put a prominent "click here to unsubscribe" link at the top of the email message. No need to scroll down to the footer to unsubscribe. What happened? Spam complaints went down, unsubscribes went up a little, then down over time.

In this context, that was a very good thing. These were emails sent to people who signed up via a double opt-in (confirmed opt-in) process, a free trial software download registration. A lot of them just wanted the free product and were quick to complain about the mail they received as a result. Even though it was double opt-in, even though it was clearly spelled out at the point of capture.

Of course, an easy unsubscribe is NOT a substitute for permission. You can't just buy some list and start mailing it and say "but it's easy for people to unsubscribe." That's the kind of thing that'll get you blacklisted by Spamhaus or get your ESP account terminated for violating ISP and ESP permission requirements.

But if you make it as easy to unsubscribe as it is to hit "report spam," you're likely to get a net positive impact to your sending reputation.

Does anyone at AT&T netops read Spam Resource?

That's a novel way to request unblocking: Boing Boing's Cory Doctorow recently posted a request for an AT&T representative to help assist with getting his mail server unblocked.

Feedback Loop (FBL) Resources from M3AAWG

Industry group M3AAWG (the Messaging, Malware and Mobile Anti-Abuse Working Group) just published an overview of what ISP Feedback Loops (FBLs) are and how they work. They've also included a comprehensive list of known ISP Feedback Loops. Click here to check them out.

Making it Easy to Unsubscribe (#1)

Found on the web: Gina Lofaro explains the user experience of finding it hard to unsubscribe. What galls me is that the list owner actually decided it was wise to argue the law with an angry subscriber. Knock that off! If she wants off the list, say OK, thank you, and it has been handled. She might not be a lawyer, but neither are you, and if you want to have any hope of selling her something ever again, maybe don't be snotty to her when she needed your help. And the subscriber is actually right -- that email SHOULD have had an unsubscribe link or option specified in the email message.

Love that e-card.