Email Marketing – How to Avoid the Spam Blockers and Filters

Wed, Apr 8, 2009

Email Marketing, Site News


Email is a great tool and a brilliant way to get your marketing message seen by your prospects, but it has also become a tough challenge in today’s online world. Any e-mail marketer will tell you that the hardest part of e-mail marketing now is simply getting your message read by the intended recipient. Why? Because spam.

Spam constitutes a huge percentage of all email sent. In order to stem the rising tide of spam, the spam filtering software has had to become more and more aggressive, meaning (unfortunately) that a reasonable proportion of legitimate email now gets marked as spam, and is either rejected altogether, or is delivered into the dark abyss of the junk/spam folder, never to see the light of day.

If you’re planning to branch into e-mail marketing—and you should!—here’s how to give your e-mail the best chance of achieving the Holy Grail of Prospect Inbox Joy.


To protect users from spam, ISPs and major webmail providers are continually developing and upgrading software programs to identify and prevent unwanted messages.
Spam blocker applications often work directly on the ISP’s mail servers, refusing to deliver e-mails before they even get within sniffing distance of the inbox. Lower-level filters review incoming mail and divert messages they deduce to be “unwanted” directly into a “junk” or “spam” folder.

Sadly for legitimate e-mail marketers, blockers and filters often make mistakes—euphemistically known as “false positives” within the industry. They occur when completely desirable and legitimate e-mail is identified as “spam” by a filter, which happens because text, graphics, or images in the e-mail trigger the filter for invalid reasons.


What follows is some advice about how to avoid the dreaded spam filters and get your e-mail delivered to your prospects’ inboxes, on time, every time.

Test. Test again.
Before sending out your mailing, perform a “dry run”. Try viewing your email on different operating systems and with different e-mail programs. You may wish to arrange a small mailing list of friends or colleagues to trial your mailings on first, in order to get swift and honest feedback.

You should also set up a number of email accounts with the various free (major) webmail providers—Yahoo, MSN, Gmail. Use different spam protection settings on the accounts. If your mail hits the junk box (or worse, doesn’t get delivered at all) with any of them, you have more work to do.

The most common filter out there is Spam Assassin. The great thing about it is that for every email that it flags as spam it explains exactly why it thinks the email is spam.
Like many filters, it uses a scoring system. When a message racks up too many points, it defines it as spam. You can see what tests it runs on your emails here—it makes for fascinating reading. You should run your newsletter or marketing email through an online spam-score checker tool like this one before sending it. Generally, a score of 3 or higher will be liable to be identified as spam.

Don’t use a lot of images
Having a lot of images in your email increases its spam score.

Avoid tiny fonts
Filters often see tiny type as a sign that marketers are trying to embed harmful elements.

Don’t use spammy terms in your email, especially in the subject line
It’s best to use your subject line to illustrate some customer benefit or solution to a problem. Don’t use it to be cute or overly personal. Don’t overuse punctuation, caps, tired and obvious marketing phrases such as: “While supplies last,” “Last chance to save,” or “Call for a free quote.”, and avoid words like “free,” “win,” “now,” “click here,”, etcetera.

Send messages from a real name
If the “From Name” field of your e-mail contains symbols, numbers, or other junk, your message has a much greater chance of being labeled spam.

Don’t get blacklisted
Besides using a set of rules to determine whether email is spam, blockers also use data from feedback and complaints, and from delivery patterns. That includes sending mail from a server that is guilty of a high number of bounce backs or which has a history of being used for spamming.

Once you’ve been identified as a spammer, it can be tough to convince an ISP or blacklist administrator that you’re not one. Sometimes it might even be impossible (some blacklist administrators, like jaded cops, have become unreasonable and aggressive through long years of having to deal with idiots.)

Pay attention to your formatting
When formatting your email, keep it simple and professional. Excessive use of different colors, fonts, sizes, images and so forth will result in a higher spam score. Keep your email as clean as possible, and stick to only a few different font types and sizes.

Be consistent
Use a template if you plan on sending newsletters consistently. This will make sure that all your newsletters look and feel the same. It will also add a touch of professionalism and branding to your newsletters

Always use Double Opt-in
Always, ALWAYS make your mailing lists double opt-in. “Double-opt-in” means that when a user subscribes to your mailing list, they will be sent an email with a link that they must click on to confirm their subscription.

The reason this is so important is that many people accidentally enter an incorrect email address. Sometimes people even add someone else’s email address maliciously. When that person receives a newsletter they did not subscribe to, they will assume they have been spammed, and your newsletter (and possibly your mail server) will be reported as spam.

Include unsubscribe and contact information in your email footer

Every newsletter you send out should contain a way for the reader to unsubscribe. You should also display your contact information clearly and completely, as this greatly increases confidence in your email and your company. Both of the above requirements are law in the United States.


Avoiding spam filters when sending out legitimate mailings can be time consuming. As your mailing list grows, however, it can prove to be a hugely beneficial exercise. If you apply all the techniques mentioned above, increases of 1000% in your open rates are quite achievable. Good luck with with your email marketing endeavors, and enjoy the information. Cheers!

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15 Responses to “Email Marketing – How to Avoid the Spam Blockers and Filters”

  1. TriXie Says:

    God it just reminded me of all the trouble our marketing company had getting off a blacklist once we found ourselves on one. The server we were using had a bad reputation, unbeknown to us, and was banned by several of the major blacklist organizations. They can be HUGELY frustrating to deal with. One guy in particular used to just hang up on us every time we called!

    DON’T GET BLACKLISTED, people. The headache you’ll get is far worse than the one you’ll incur just doing the right thing in the first place–in our case checking out the email server’s reputation before we signed a contract to hire it for a year, lol.


  2. Steven Acer Says:

    Sound advice, Mogul. Wish I’d had it before I started my last email marketing venture!


  3. seanlittle Says:

    do u have to have ur phone number in contact info? is cell ok?


  4. Salwa Says:

    Nice article, great tips thanks! I am just starting in email marketing and your tips will sure come in handy!

    Salwa’s last blog post..Traffic Monday: Ways to Increase Traffic


  5. Karlstadunix Says:

    what autoresponder did you use ?


    • Mogul Says:

      @ Karlstadunix

      We used the paid version of Get Response. It seemed to do the trick. There’s a free version they do which is also decent, but it will include ads in your emails, so I wouldn’t recommend it. If you have some time and some programming skills I’d advise you just to write your own; it’d be no huge task.


  6. sierra56 Says:

    @seanlittle Uhm not 100%, check the CAN-SPAM law stuff… my suspicion is yes?


  7. Richard Says:

    Nice list, it’s also worth setting up DKIM, and SenderID for your domain. You’ll get a higher percentage of emails into Yahoo! if you have DKIM setup.

    Richard’s last blog post..Internet trends


  8. Mogul Says:

    Truthy, Richard. We bumped up our Yahoo deliverability by 10-15% by taking those measures. Cheers!


  9. John Says:

    I think a good idea is to take a look at the emails coming into your spam filter and do the opposite of what they are trying to do. Make the emails sound unique and geared towards the intended recipient.


  10. Eva Fonda Says:

    Very informative post. All points are taken.


  11. Maye Says:

    I was searching for a solution for not getting my emails spammed and voila… found this! Thanks for sharing.


  12. Ronald Says:

    I was once blacklisted. Damn! I still haven’t figured what went wrong.


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