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How to Avoid Email Spam Filters and Folders

By February 21, 2019April 8th, 2019Email Marketing, How To Guides

As email marketers, some of the bigger obstacles we face are spam filters and folders. That’s why we designed the following infographic – how to avoid email spam filters and folders.How to Avoid Sending Email that Ends Up in the Spam Folder and FilterDownload infographic here.

In most cases, spam filters are really good at their job. But what if they make a mistake? Or what if you’re triggering the spam filter and don’t even know it?

Full Color Spam Can ImageWhat makes a good girl go bad, a hero turn evil, a well intending email into spam?

Your email ROI reflects the overall success of all of your email campaigns. This is a classic tale of a protagonist, in this case, a marketing email making a few wrong turns and ending up in the email equivalent of purgatory… the spam folder.

Neil Patel: “In the past, the only way to make sure that spam filters didn’t mark your emails as spam was to make sure that the content of your email wasn’t spammy. It used to be easy. Spam filters searched for certain flagged words and language and then scored your email based on how many of those phrases your emails contained. If your spam score was low, your email went into the inbox. If it was high, it would never make it in.”

The same factors still apply today, except email providers search for spam using even more advanced methods. Read Neil Patel article about What determines whether an email hits the inbox?

But before we get to that, let’s answer some questions.

What is a spam folder and why do emails end up there? 

Emails are sent to the spam folder when the spam filter determines they are, well, spam. The spam filter stops emails from going to an inbox.

If your emails are going to the spam filter, it means you have low deliverability.

Deliverability means: a way of measuring the success rate of emails making it into the subscriber’s inbox.

Deliverability depends on a whole bunch of things. One of those things is sender score. Sender score is determined by an algorithm that looks at the rating of an IP address associated with the outgoing mail server.

It sounds complicated, but here’s the main takeaway…

Email marketers should probably know their sender score.

Sender Score Image(Hint: You can find sender score here)

Your sender score all depends on your IP address and mail server.

So what is a spam filter?

Different servers have different filters, which use a unique criteria for labeling spam. So while your email might slide through on some servers, like Gmail, it could get stopped by others, like Hotmail.

Filters can either be installed by the user or by the email program. Users can manually pick features to filter the spam, while email programs have automatic systems.

email clients logoThere are a few automatic systems that filter spam.

Bayesian filter is one of the most prominent. It’s used by Outlook, Thunderbird, and Apple mail.

This system filters mail out based on what other people are marking as spam. Bayesian looks at the traits of those emails and then looks for them in other emails.

If you have a trait they deem”spam worthy,” you will be docked points. Once an email reaches a certain number of points, it’s sent to the spam folder.

The challenge/response is another type of spam filter. These filters look to see if you’re in the recipients’ address book. If you’re not, they consider you a spambot and send you a followup to confirm you’re not.

The best way to combat this is to have your customers add you to their contact list. But more on that later.

Large companies, such as Google, use email firewalls. Firewalls are essentially giant spam traps on top of the filters.

Firewalls are triggered easily, so it can be very difficult for your emails to get through on the first send.

Firewalls are typical at large companies, so if you’re customers are using their work email, you might see low deliverability rates.

While these are just a couple examples of spam filters, there are many more and it can get quite complicated.

Here’s some bedtime reading on spam filters and here’s some more. Enjoy.

How does getting caught in the spam folder negatively affect your business?

If your emails are ending up in the spam folder, it’s likely your customers will never read your emails.

For you an eCommerce shop, this means your customers will never place an order.

Basically your emails will become completely ineffective.

Email Spam Trap City

You could get a reputation as a spammer and then you’re in Trap City, population: your brand.

We don’t want this to happen, but it’s so easy for a few poor decisions to make a good email go bad.

So let’s dig into it and keep your emails in the inbox.

Here are all the parts of your email that can trigger a spam filter:

Subject Line
Email Design
Unsubscribe Link
Email List

Alternatively, you can jump to the 25 ways to avoid email spam filters and folders here.

Once upon a time, there was a simple and honest newsletter…

You’re the email marketer for an eCommerce shop designing this simple and honest newsletter.

It was assigned to you by your boss, Mark.

He tells you this email should alert customers about an upcoming sale promotion.

Sounds a lot like an email blast, no?

You go to work designing a perfect email and after getting it to a good place, Mark takes look.

“You need to spice up that subject line. You have to hook them in, so give it some flair,” he says as he runs his hands through his frosted tips.

Writing subject lines

Anyone with frosted tips past 2001 should always be ignored. Subject lines are a major reason for emails getting trapped in the spam folder.

Keep your subject line simple and direct. If it sounds gimmicky or deceptive, chances are the spam filter will think so, too.

Spammy Subject Lines

Most sources say to avoid too many uppercase LeTTerS LiKe ThIs, but what about the emojis we love?

Campaign Monitor says they haven’t seen emoji’s trigger filters, but be mindful that some platforms don’t support emojis– Outlook for example.

*Fun Fact*
According to eConsultancy, the snowman emoji is the best to send with an open rate of 65.72% vs the average. While a pointing finger emoji is the worst with an open rate of -9.52%.

So your childhood truths are confirmed. It’s not polite to point and Frosty the snowman really is a jolly happy soul.

Spam filters will read your emails.

And they will catch misleading claims alluding to a prize and the hidden conditions in the body and footer.

Spam filters go into action when a subject has a “Re:” or “Fwd:” especially if there hasn’t been previous back and forth of communication.

In fact, avoid all these words.

You’re smarter than Mark, but for sake of the story, let’s say you took Mark’s advice. Emojis, caps and money symbols galore are in the subject line.

It does seem attention grabbing and you’re about to send it when Mark’s twin brother, Chad, walks by and asks to take a look.

“Hmm…the subject line is good, but the body is lacking. Add a bunch of graphics, links– anything to build up that body!”

He says this while flexing his muscles and swigging a protein shake.

Don’t let your body go

Even if you get past the filter, customers are going to delete emails that don’t have unique content, incentives or exciting news. The same goes for brands sending emails too often.

But even if your content is gold, there are so many little ways to be labeled as spam. All the trigger words and same rules apply to the body copy.

Body Language 

Think of it like a party with the ideal ratio of males and females.

Equality between text and images…and the sexes! 

Don’t include one giant image or a bunch of small ones without supporting text.

If there isn’t enough text, spam filters will think you’re trying to trick them and that makes them angry.

Ratio should also be considered with links. Don’t add a plethora of links and ESPECIALLY make sure you’re linking to legitimate, credible sites.

Sloppy Joe Image

Nobody likes ‘sloppy’ unless it’s followed by ‘joe.’

Be extra particular when it comes to your grammar, spelling and coding.

Consider including the date somewhere in the body so filters know the email is current.

The issue is, you’ve now listened to Mark, because he’s your boss, and Chad, because his muscles scare you.

The email has morphed into something completely different.

The infamous unsubscribe link

You add in an unsubscribe link to your Frankenstein of an email when Javier stops by your desk to take a look.

Mark, Chad and Javier are triplets.

“The unsubscribe button is in plain site. It’s like you want them to unsubscribe. Hide it!”

Unsubscribe email linkHe goes on, “And don’t use the support email address, it will fill up our inbox. Make it a do-not-reply address.”

This advice isn’t surprising advice from someone who deadbolts his door at dinner parties so guests can’t leave.

While no marketer wants unsubscribes, they happen. It depends on your industry, but according to MailJet an unsubscribe rate up to 1% is within the norm.

The CAN-SPAM Act says the unsubscribe option must be included in the email, and not difficult to find.

It also has to be a working link for up to 30 days past the send date, and you must honor unsubscribe requests.

Don’t be a triplet named Javier.

If your customers want to unsubscribe, let them. It keeps your lists cleaner and allows you to segment lists with greater precision. We’ll go into that in just a bit.

Why don’t you want to hear from customers?

Your ‘from email address’ needs to be a legitimate sending address. ‘No-reply’ email addresses can get caught up in the spam filter. This a bad practice and might effect your overall email domain reputation. Our recommendation is never to send from a “do not reply” email.

And if they don’t get caught in the filter, recipients are more likely to mark/report your mail as spam according to eConsultancy.

Enough abuse reports and the server you use to send mail will be blocked.

This is called being blacklisted.

In other words, it will become impossible to avoid email spam filters and folders.

No-reply addresses will never be added to your customers address book and frankly make you seem like you don’t care about customer opinion.

No Reply Email Example

Letting customers know they can reply to your emails, even if they’re automated create a better customer experience. More importantly, it will encourage communication between your brand and customers, along with improving engagement rates.

Engagement rates could be considered open rates and/or click rates. These, along with the purchase rate or the number of people placing an order after receiving an email are critical when your email’s effectiveness.

Back to the story.

So now that the subject line is cheesy and the unsubscribe link is hidden, per the wishes of the triplets, it’s time to pick the email list.

Email blast them all

This leads to questions. Should the email be sent to active customers, inactive customers or everyone in your email list, including people from a Tweet-Up in 2008?

You ask Sasha, the social media manager.

She buys Twitter followers.

“Send the blast to everyone,” she says, “and everyone’s mom.”

“I bought a list of email addresses, potential leads in there, so email them, too.”

Define the Email Recipients

You may have already listened to the triplets, but DO NOT LISTEN TO SASHA.

Using purchased lists are a sure fire way to damage your reputation and be seen by filters and customers alike as a spammer.

While you may want to send emails to inactive customers, subscriber engagement is a factor that determines your spam rating.

If engagement rates are low – your opens and clicks – campaigns will likely all be lumped together as spam.

Make sure you’re communicating with customers consistently so the connection doesn’t go stale and don’t forget to send email at the best days and times.

Require your subscribers to double opt in. That way you’re sending emails to those who want it.

Send emails to customers based on the way they shop.

Email Segmenation Conditions Rules Image

Are you tracking the way your customers shop? Break up your lists to target specific segments. It’s super easy to do this with Remarkety.

For example, instead of sending an email blast for 30% off a specific brand to all your shoppers, segment the list.

Consider only sending that email to customers who have bought from that brand or a similar brand.

This will help you keep lists cleaner.

Consider asking customers to add you to their address book, that way your emails definitely make it to the inbox.

Moral of this email tale

Your innocent little email has gotten a bad girl makeover.

It’s like Sandy in Grease.

But instead of riding off in a flying car with John Travolta, your email lands itself in the spam folder.

Your open rates and click rates are in the fractions of a percent. Your purchase rate is even lower and now the triplets are lambasting you on Twitter.

Through cheap tricks and deception, you’ve become a spammer.

Alright, alright you can stop screaming. It’s just a story, remember? You know the rules, now don’t break them.

If you do, it won’t just be your emails that get canned, but your reputation, too.

Keep in mind, spam filters aren’t dumb and aren’t easily tricked. Sure, they can erroneously send your emails to the spam box, but if your emails are driving opens and clicks, you should be good.

If in doubt, think what the wise Woodsy Owl would say.

“Give a hoot, don’t pollute!”… people’s inbox.

25 Ways to Avoid Email Spam Filters and Folders

Didn’t catch everything in the tale? No problem, here’s a checklist of 25 ways to avoid getting canned in the spam folder.

1.) Avoid these words in both subject lines and body of email.
– guarantee
– 100 % free
– $$$
– !!! or an excess of other symbols
– Attention!
– Act now!
– T_e_x_t_w_i_t_h_g_a_p_s
– Re:
– FWD:
– Cash
– Dept
– Casino, Sex and Supplements related words
– Anything else that you personally hate to see in your inbox ;-)

2.) Don’t be deceptive in subject line and start with “Re:” or “Fwd:”

3.) Keep the body format simple – don’t cram in too much information or make an elaborate layout that may not look good on mobile or tablet devices

4.) Don’t have an excess of images, or one giant image – you want to have an equal ratio of image and text

5.) Don’t add too many links in the body

6.) Only link to credible sites

7.) Don’t be sloppy with grammar or spelling- these errors can trigger spam filters

8.) Be precise and professional when coding HTML – be careful when converting a Microsoft word file

9.) Do not create an HTML link that is just one giant image

10.) Don’t attach items to emails

11.) Include easily accessible unsubscribe option- don’t hide the button

12.) Make sure unsubscribe option works for up to 3o days- respect all unsubscribe requests

13.) Have subscribers double opt in to avoid being black listed

14.) Ask subscribers to add you to their address books

15.) Don’t use no-reply from addresses like “”

16.) Avoid sending emails with “test” in the subject line

17.) Must include physical mailing address

18.) Don’t use purchased lists

19.) Don’t send to stale lists – a recipient typically goes stales after 6 months

20.) Don’t send to email addresses that have bounced your emails repeatedly (most ESPs do this automatically)

21.) Keep customers engaged through product review requests, order followups and general feedback requests so they don’t become inactive. Inactive customers lead to low opens and clicks

22.) Include the date in email to show it’s current

23.) Avoid changing the from name frequently

24.) Make sure any claims in the email are honest and real – don’t offer something and then include hidden conditions

25.) Reference your domain in emails AKA  sender policy framework (SPF) – SPF is pretty much the standard for email authentication. It compares the sender’s actual IP address to a list of IP addresses authorized to send mail from that domain. This is important to keep in mind when using a third party to send your emails like Remarkety, SendGrid, MailChimp, etc.

So now what?

For starters, you should be feeling more confident about sending emails that go to the primary inbox. If you aren’t and have questions drop us a line or send us a Tweet.

Then you can look at hilarious Spam advertisements. After that, you should read these other articles.

Online shopping trends reveal best days and times to email customers
eCommerce email marketing best practices
How to grow sales without coupons 


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    Infographic by Christina Ohanesian
    Photo Credits: Tumblr, Superb Wallpapers, TheBeeroness