Spam Filter Triggers to Avoid

The spam filter game is rather simple: you receive points for every "spam technique" you employ and you lose points for every best practice you put into place. Just like golf, you need a low score to win the game.

There are many different aspects of your email message that receive a positive or negative point value, such as message encodings, http proxy servers, trusted relays, Habeas accreditation, sender authentication, HELO and rDNS matching, etc. Many of these are somewhat technical and difficult for the beginning email marketer to address. After all, it's hard to deal with something when you don't even know what it is!

So what's a newbie email marketer to do? I suggest you start with the obvious - the one aspect of your email marketing that you can actually see - your content!

Now it's true that today's sophisticated spam filters are not relying solely on the message content as they once did. However, it is still a factor, and since it is the easiest issue for most marketers to deal with, it's one that definitely can't be ignored.

And here's an interesting point to keep in mid - while you can follow the technical rules and earn negative points (remember, negative is good) in your message header, in your relays, in your MIME types, etc there is nothing you can do to your message content to earn negative points. Your content can only get slapped with positive points, so you might as well do all you can to eliminate that possibility, right?

Subject Line Triggers

Your subject line is the first piece of your content that the filters encounter, and it's actually scored differently than the rest of your message body. Here are a few things you want to watch out for:

Subject includes spam trigger words
Subject contains g*a~p^p.y or g a p p y text
Subject starts with dollar amount
Subject talks about losing pounds
Subject is all capitals
Subject has exclamation mark and question mark
Subject contains an English UCE tag
Subject contains an Japanese UCE tag
Subject contains Korean unsolicited email tag

It's crucial that you avoid and eliminate any common spam words in your email subject line and message text. And don't try to hide suspect words by using asterisks or dollar signs. The filters have already caught on to this technique and they'll ping you with a pretty point value.

What words should you avoid? Well, some of them are obvious, such as anything of a sexually explicit nature, viagra, other drug names, and so forth. But some of them are less obvious such as "call now" or "click here". And some are even down right contradictory, like "unsubscribe". After all, we've got to maintain Can-Spam compliance, don't we? Well, as long as we don't mention Can-Spam compliance, that is. Yep, you guessed it, that's another trigger for the spam filters!

Subject Matter Triggers

In addition to specific words, you also need to avoid certain subject matter and message formatting. For instance, if your message contains too many blank lines, you'll get a few spam points. Unusually spelled words can trigger spam filters and so can having two or more consecutive words without any spacing in between, so be sure to proof read and spell check your messages before sending them out.

Believe it or not, telling your reader how they can be removed from your mailing list also adds a few spam points to your message. Which only goes to show how important it is to follow all the best practice and earn yourself as many negative points as possible.

Additional subject matter that can trigger the spam filters includes:

Your message includes excessive blank lines
Your text was disguised using base64 encoding
You included a quoted-printable line longer than 76 chars
Your message contains a URI which was truncated
You used gappy words, attempted to hide or obfuscate words
You have two or more words crammed together into one word
You message discussing search engine listings
Your message body includes 8 consecutive 8-bit characters
Your message contains an URL listed in a public blocklist (currently matching approximately 10 blocklists)
You talks about banking laws
You include a removal phrase right before a link
You talk about lots of money
You claim the reader can be removed from your list
You claim your reader wanted this ad
You talk about how to be removed from mailings
You offer an alert about a stock
You include information on growing body parts
You claim not to be selling anything
You claim to be in accordance with some spam law
You claim your reader has registered with some kind of partner
You talk about Oprah with an exclamation!
You talk about 'acting now' with capitals
Your message mentions investment advice
Your message says that prices aren't too expensive
Your message talks about hidden charges
You refer to prizes
Your message body claims it is a one-time ad
Subject indicates sexually-explicit content
You include "suspect" words in all caps

HTML Formatting Triggers

And finally, the way you format the HTML version of your email message can trigger the spam filters. Here are a few pitfalls to watch out for:

HTML message is a saved web page
HTML with embedded plugin object
HTML contains far too many close tags
HTML background color other than white
HTML font size is large
HTML font color similar to background
HTML font face is not a word
HTML includes a form which sends mail
HTML has a low ratio of text to image area
HTML obfuscation
HTML has unbalanced "body" tags
HTML has unbalanced "head" tags
HTML has "bgsound" tag
HTML message contains bad tags
HTML elements are non-standard
Message has HTML IFRAME tag with SRC URI