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Spam Filters: The Truth about Email Marketing Gatekeepers

Spam filters are curious things. Ever-shifting in their discretion, the rules are always changing, sometimes in big ways, sometimes in smaller ones. But there are some rules that remain constant about spam filters, and if you keep them in mind when you write your campaigns, you'll get much better than average delivery rates, which means beating the discouraging industry standard, which sees as many as 20% of emails never making it to the inbox.

If you've ever wondered specifically which words tend to trigger spam filters, we've listed the obvious and less obvious ones.

Obvious words/phrases that set off spam filters
Earn your degree
Reduce debt
Bad credit
Home mortgage
Easy income
Problem with shipping
Work from home
Problem with your order
Cialis, Viagra and the like
Pay your bills
Cheap meds
Free laptop
Weight loss
Job alert
As seen on Oprah
Replica watches
Gift card


Now we move on to the less obvious phrases and words. While we don't expect to see any of the phrases or words listed above in your emails, you might be tempted to use these:

Less obvious spam trigger phrases/words:
Take our survey
Huge sale
Discount coupon
% off
Store credit
Holiday savings
Huge deals
Free gift
Free download
Free shipping
Discount shipping
Regarding your order
Symbols, urgent pleas and more

Spam filters block a lot more than words and phrases – they also block symbols, writing in all caps, aggressively urgent language and more, especially in subject lines. Do the following and you're almost certain to find your emails dumped in the trash bin:

Use over- excited language, all caps – or both
If you're using phrases like "SUPER SALE!!!!!" "INCREDIBLE DEALS!" "YOU WON'T FIND THIS ANYWHERE ELSE!!!!", your mail will get dumped.
Use dollar symbols, exclamation points and more
Avoid the dollar symbol like the plague, as well as the exclamation point if you can help it. These are huge red flags for spam filters.
Use a huge sense of urgency
If you think that phrasing like "buy this now!!!!" "Deal ends tomorrow! Don't wait!!! will get you into the inbox, think again. The pressure cooker is an old trick used by spammers. You do not want to be seen as one of them.
Using creativity to sidestep spam filters


With all the words, phrases and writing styles that can set off red flags, maneuvering around spam filters might seem a little overwhelming and even impossible. But don't fret. There are things you can do that simply require a bit of creativity on your part.

The most basic thing you can do is focus on your subject line. The subject line plays a huge role in getting your email past filters or blocked. Take the time to come up with phrases that say what you want to say, but use none of the words or styles that draw attention to your emails.

Here are three examples:

The bad (too spammy):
Save 50% off purses at our huge holiday sale!

The good (short and to the point):
Get set for spring: hot handbags, half off

The bad (too long and boring):
Prices slashed on all gardening equipment including shovels, gloves and more

The good (offers something of value):
10 top products that make gardening easier

The bad (too tech-y):
Processing chips and deluxe K40 sound cards on sale

The good (creative and intriguing):
Annual sale on components: Get speed and sound for your PC

A few tips on format

A few things to remember when sending out your emails if you want to sidestep the junk file:

Your subject line is very important. Cut out the spammy language and you've won half the battle.
Don't send a naked email with just a little bit of text, a single photo or anything of the sort. Spammers do this all the time – don't fall into the same trap. Deliver good content.
Keep your code clean. Don't skimp on your time setting up the HTML code. Spam filters get confused by this and often dump emails with lousy code right in the spam file.
Use a spam checker. A spam checker will flag most words that could stop your email from reaching its destination. Benchmark features a solid spam checker right in its Email Builder, so you can change your layout and copy and check your potential spam rate before your email goes out ti the masses. Here are a few screen shots:


Once you're done with your layout, click on the Spam Check button and you'll see which words and links are most likely to torpedo your delivery rate.

Look for sinking open rates
One week you're having 30% open rates, the next week, 10%. So what happened? You probably sent out an email with too much spam and a big portion of your send never made it to your customers.
Watch those bounces
Your bounce rates play a big role in finding out if you have a problem. If you're getting way more messages than usual back, there's a pretty good chance at least some of them will contain messages from the email exchange stating why the email service provider rejected them.
Check your IP address and see if it's on a blacklist
If you're seeing your open rates sink like a stone, there's a fairly good chance you've sent out something that was flagged as spam, putting your IP address on a blacklist. This is easy to check. All you need to do is go to a service like www.blacklistedip.com, type in your IP address and see if it comes up on any blacklists. If it does, contact your email service provider to see how to resolve the issue.


Getting past spam filters as an email marketer is part science and part art. It's not always easy. But once you develop good habits and follow them every single time, chances are you'll see steady open rates and no drama whatsoever.

Benchmark Email works with several organizations including Habeas and the Email Sender & Provider Coalition to keep delivery rates sky-high. Find out why Benchmark is a Spam-Free Zone.

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