CLIP & SAVE GUIDE to Avoiding Spam Filters

By Debbie Weil
Publisher, WordBiz Report

Should you omit the word bleep? Hint: it starts with an "f." Ends with an "e." Has four letters.

We're being censored

In order to get past spam filters labeling their mail as "false positives," some e-publishers are cloaking trigger words with made-up spellings like "sp^m" or "fre*e." They're also using circumlocutions such as "To leave this list and never hear from us again" instead of "To unsubscribe."

It looks silly and unprofessional. I can't stand the idea of being muzzled by anti-spam technology.

But it's true. Filters are becoming a business-critical problem for opt-in email marketers and newsletter publishers.

With filters operating at the ISP, corporate firewall and desktop client level, it's harder than ever to get legitimate email messages successfully delivered. The filters are neither stemming the tide of sp^m, nor accurately diverting it into junk folders.

CLIP & SAVE guide

What can you do? You don't have to become an expert but you need to know enough to avoid the most common triggers. Educate yourself on the basics of spam-filtering with our mini CLIP & SAVE guide.

(The CAN-Spam Act of 2003 was passed into legislation after this article was originally published. A good reference on how to comply with the new rules is How to comply with the CAN-Spam Act of 2003 by Ralph W. Wilson.)

Mini tutorial on SpamAssassin

Here’s a selected list of just a few of the hundreds of terms blocked by SpamAssassin, the most widely used network-level filter.

(Note: SpamAssassin uses open-source technology aimed at UNIX systems. My non-techie interpretation of this is that network administrators can configure SpamAssassin however they want.)

Some common trigger words or phrases:

- subject line starts with “free”

- subject contains FREE in all caps

- the word “free” in certain phrases (free offer, free leads, free access, free preview)

- certain words like “guarantee” in all caps

- words like “unsubscribe,” “leave,” and other list removal phrases

- using font sizes that are 2 + or bigger

- background in an HTML email that isn’t white

- HTML font color is gray, red, yellow, green, blue, magenta or “unknown to us”

- claims compliance with spam regulations or with US Senate Bill 1618 or House Bill 4176

- urges you to call now or claims you can be removed from the list

- the phrases: what are you waiting for, while supplies last, while you sleep

- asks you to click below

- uses a Nigerian scam key phrase such as “million dollars”

- money back guarantee


How can you avoid all of these? The answer is you don’t have to. SpamAssassin uses a rules-based system to filter mail headers and body text.

Basically, it’s a point system that assigns positive (it’s spam) or negative (it’s not spam) scores to a long list of trigger words, phrases and message headers. You have to reach a certain total before your email message is classified as spam and diverted.

If you’re accumulating negative as well as positive points, you may be under the threshold. For example, using the phrase “if only it were that easy” assigns you +2.0 points. “Free preview” gives you +1.7 points while “free trial” gives you only +0.1.

We believe the most common setting for the trigger score is a total of +5. You geeks out there can jump on me if this isn't correct.

(One reader has kindly informed me that the text version of this issue of WordBiz Report scored a +7 through his system's settings. So much for made-up words. Oh, and I'm guilty as charged. We do say "click below" in the text version.)

Want to waste some time?

Scroll through the loooong list of trigger words, in multiple languages, on SpamAssassin's site. It’s fascinating reading.

Click on this link to peruse SpamAssassin's test list.

Good articles about SpamAssassin from Ezine-Tips

Snapshot articles by Janet Roberts that provide good explanations in a few words:

Inside a Spam Assassin Report

To ‘Unsubscribe’ Might Trigger Filters

How to Avoid the ‘U’ Word

Three useful articles by online marketing expert Ralph F. Wilson

Anti-Spam Approaches

20 Ways to Outsmart Spam Filters

250 Words & Phrases That Trigger Some Spam Filters

More about avoiding filters

The Permission Emailer's Guide to Avoiding Filters
I highly recommend this special report by MarketingSherpa.

EmailSherpa's Top 5 Ways to Avoid Filters
Good article that explains the types of filtering that trash your emails.

Email filtering: killing the killer app
Long article by Geoff Duncan for TidBits, the venerated Mac community. I love the title.

The true costs of spam filters
Quick, informative article by Network World columnist Paul McNamara.

Spam and email filters – reader solutions
by ClickZ columnist Paul Soltoff

Spam: E-Marketing's Alter Ego
According to a new Jupiter report (Marketing and Branding Forecast: Online Advertising and E-mail Marketing Through 2007), "e-newsletters and marketing emails will lose their luster -- that is, messaging and branding effectiveness."

Good resource sites

CAUCE (Coalition against unsolicited commercial email). It's free to join and probably a good thing to do.

Anti-Spam resource site

SpamCon Foundation to reduce spam

SpamCop (different group) to report spam

Electronic Frontier Foundation’s position on junk email

Stay informed about legislative efforts to combat spam

Complete text of the CAN-Spam Act of 2003

How to comply with the CAN-Spam Act of 2003

SpamCon Foundation Law Center

Spam laws in the US, Europe and other countries

Report to the Federal Trade Commission on UCE (unsolicited commercial email)

Recommended desktop anti-spam filters

SpamNet is a popular anti-spam filter for the end user


Challenge / Reponse Software



Know of other great resources? Email me at dweil @ wordbiz dot com and I'll update this list.

About Debbie Weil

Debbie is publisher of award-winning WordBiz Report. She is a former newspaper reporter and editor with an MBA and corporate marketing experience. She brings the discipline of a reporter's eye and an editor's pen to marketing with e-newsletters, Web site content and Weblogs.

Read her blog at Subscribe free to WordBiz Report at Purchase e-books about marketing effectively with e-newsletters and blogs at

This article was first published in the Sept. 25, 2002 issue of WordBiz Report.

© 2002 - 2004, Inc. May not be reprinted without permission.


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