• by daniel.c , Melinda Krueger , August 28, 2007

If you're like me, you may have been confused by the recently published article, "The Seven Dirty Words You Can't Say in Email Subject Lines (Plus 100 Others You Shouldn't Use Either)."

Not being a deliverability expert, I put out the bat signal to my discussion group, the Inbox Insiders. Founded by Bill McCloskey, this humble email list serve has come to my aid (and served up interesting discussions) more times than I can count.

"Since your spam score is a composite of many factors," I asked, "a word in your subject line, while contributing to your score, isn't enough to affect your deliverability. Or is it?"

The experts weighed in:

Loren McDonald, vice president, corporate communications, JL Halsey:

"You can see the SpamAssassin-based rules here -- which provides the individual scores that many companies, universities and spam filter software companies, etc. base their filtering on as well as many smaller ISPs....The [major ISPs] have filters that are similar to SpamAssassin...but they've evolved over time to their own proprietary rule set. So SA is a good starting point, but every company and ISP will have different rules, scores, tests, etc.

In general, single words and phrases are not likely to get an email filtered to the spam/junk folder (this is different from being blocked) - it is the sum total of scores from the various tests. The prevailing theory used to be that most ISPs would filter at 5.0 and above, then 4.0 and now apparently many are at 3.0 and above.

So, yes, content can get you filtered, but it is more likely going to be a combination of several words, phrases, not passing SPF tests, using bad code, etc., then combined with your reputation scores.... This is why smart marketers use one of the email deliverability monitoring tools...."

George Bilbrey, vice president/general manager, delivery assurance solutions, Return Path:

"Our data would indicate that very, very few delivery issues are based on keywords.... Rather, the most common problems are of two types:

1. Reputation Problems with the Server Sending the Mail: High complaint rates, unknown user rates, spam trap hits or bad sending infrastructure make the IP or domain sending the message look bad to the receiver. This is far and away the largest source of delivery issues....

2. Reputation Problems with the Content: A message containing a given URL or unusual set of words (typically very specific to a particular message or mailer) hits a lot of spam traps or is complained about a great deal. Heuristic rules at the ISP filter these messages out.

These two sources are typically well over 90% of all delivery issues."

Josh Baer, CEO, Skylist:

"It's worth noting that each ISP is different and while the big ones are more advanced, others are often still archaic. They may be using outdated tactics or old versions of software like SpamAssassin instead of the latest version. In old versions, having the text 'click here to unsubscribe' could push you over the edge and cause deliverability challenges (more recent versions of SpamAssassin are smarter).

That said, if you're looking at a particular message that isn't getting delivered to the inbox, and it has content that is racy, I definitely would try modifying the content to see if that makes a difference. It's more reactive than proactive these days -- you only think about it if you start having problems."

Ray Everett-Church, Esq., director of email policy, Habeas, Inc.:

"Unfortunately many smaller ISPs and untold thousands of businesses are still using filtering/blocking technologies that can only be charitably described as archaic and/or ham-handed. For example, I run some discussion lists on Internet legal issues and any time 'porn' or half-dozen other suspect words appear in the messages, I see bounces from a half dozen law firm mail servers. Those places also seem to be the most resistant to improving their infrastructure to deal with such obvious false positives."

So you see, dear readers, there is far more to deliverability than the "7 Dirty Words" article would lead you to believe. That's why it pays to work with experts. Sending email yourself? Consider an ESP. Working with an ESP? Ask what they're doing to monitor and improve your deliverability. Not sure your ESP is doing enough? Contact a deliverability vendor and ask for an assessment. Think improving delivery is a matter of editing your subject line? Think again.

Good Luck!

The Email Diva

Send your questions or submit your email for critique to Melinda Krueger, the Email Diva, at emaildiva@kd-i.com. All submissions may be published; please indicate if you would like your name or company name withheld.