How do you stop email falling into the spam folder?

In this article: ► How sender reputation is built ► The five factors that shape sender reputation ► The groundwork automated marketing needs before it can produce high ROI

If you work in marketing, you have almost certainly had a bulk promotional email classified as spam, and asked the obvious question…

How do I stop my mail falling into the spam folder?

In The channel you thought was obsolete is the one that works we noted that one in every six emails ends up in spam. That is not a reason to abandon email marketing, because email remains an effective tool for member communication. Here we look at how to improve the odds of landing in the normal inbox — inbox deliverability — or, put another way, not being classified as spam. Start with what sender reputation means.

Sender reputation

Behind every email server sits a spam score calculation, and each recipient’s server on your list may calculate it differently. Broadly, a higher spam score means a higher chance of being labelled spam. Conversely, the more a sender produces email that generates “good responses”, the higher the sender reputation and the lower the chance of landing in spam. Good responses are judged on factors such as how many recipients opened the email and how many clicked the links inside. Which sounds like a chicken-and-egg problem: how does an email in the spam folder get opens and clicks?

Exactly. Sender reputation has to be accumulated through a warm-up process.

A myth — is switching IP or capping volume the answer?

It is worth noting that many email providers explain this only at surface level, telling you that repeated bulk sends cause IP problems and that sending a lot of email at once gets the server or domain blocked. Without a warm-up building sender reputation, a bulk sender is indeed very likely to be treated as a spammer — but warm-up is not an IP or hardware issue. It means starting by sending valuable email slowly, so recipients are willing to interact with your brand (open and click), and your sending domain gradually builds a good reputation. A professional provider will not tell you to switch IP or cap how much you send each time to avoid getting the server blocked.

Sending a large volume of email is not the same as spamming. What matters is what you send. Send the right message and it is not spam — it actively raises sender reputation.

Five factors that raise sender reputation

(1) List hygiene (2) Personalised content that draws recipients into interaction (3) SPF and DKIM configuration (4) Image-to-text ratio (5) Subject line

(1) List hygiene Many startups, and established companies launching something new, gather email addresses from every available direction — some of them harvested online. Because those people never opted in or subscribed to the company’s messaging, they had no idea they would receive it, which produces strong resentment. Worse, some of them will report your email as spam directly, and a list carrying many invalid addresses produces a high bounce rate. Both severely damage sender reputation and the success rate of everything you send afterwards.

If your list came from people subscribing of their own accord, with a prior idea of what your company would send them, then it is what they wanted — that is why they opted in. They may even look forward to your email and open it on arrival. That is how sender reputation is built, step by step. A list constructed on that basis of mutual trust is clean and effective (it does not bounce), and we call that good list hygiene.

(2) Personalised content that draws recipients into interaction Content is king. What you give the customer in value is what the customer gives you in response — that is the strategy. We cannot only think about what we want to sell right now; what we actually need to think about is what problem we are solving for the customer. So answer the expectation they had when they subscribed, with solutions and suggestions. If all you ever send is price messaging rather than value messaging, you may get a momentary impulse but no motivation to follow the brand — unless you are already a household name to them, in which case they open your email purely to wait for a better discount.

Personalisation is a significant part of communicating with customers. Even in an auto-piloted conversation, using their name makes the customer feel you know them rather than that this is a generic promotional email. On top of that, because they have a memory of your brand, they do not read it as spam. More advanced personalisation works with a CRM to distribute different messages according to preference, so that someone interested in sport does not get buried in investment information. Automated marketing uses the system’s tagging to deliver the right messages to the right persons at the right time.

An eDM usually carries a call to action, and precise messaging produces precise clicks and traffic. More customer response also helps build good sender reputation.

Getting personalised communication right lifts click rate by 14% and conversion by 10%

(3) SPF and DKIM configuration These are two technical settings that have to be made at DNS level. In short: the domain authorises which email servers may send on its behalf, so the world knows you are the genuine sender, and a digital signature is added so that when the recipient’s server receives your mail it can check the email header and confirm you are who you say you are rather than a phishing sender.

These two settings matter enormously, because on the internet anyone can pretend to be some bank’s sender in order to defraud. If recipients cannot establish that you are the genuine sender, you are very easily treated as a spammer.

(4) Image-to-text ratio To save time, plenty of large companies still use a single poster as the entire content of an eDM, with no text in the email at all. Many recipient servers treat this kind of mail as spam, for the same underlying reason: most spammers do use email as a shortcut for opportunistic phishing, and will not spend the time laying out proper image-and-copy design. eDM also needs to handle mobile responsiveness, and plenty of email clients will not pre-load images from an untrusted sender at all. All of that adds to the spam case. Our general advice is at least one or two paragraphs of text, and to make sure that with images unloaded the customer can still tell what you are saying — that is what makes them click to download the images, which in turn helps sender reputation.

(5) Email subject Recipient-side spam filters do not much like seeing SPECIAL / OFFER / COUPON / DISCOUNT in a subject line, particularly in capitals; accumulated experience has taught them to classify these as spam.

Certain other spam keywords deserve attention too. Free, guarantee, credit card, sex, no cost and similar are best avoided, and a run of symbols — ”!!”, ”??”, ”$$” — appended to those keywords makes classification as spam very likely.

***** One further point to watch: bulk-sending without addressing the above is very easily read as spamming, and the day-to-day operational addresses on the same domain get classified as spam too. At that point people stop receiving your important quotations and product information.

Email marketing is a proven promotional method, and it needs professional configuration to raise inbox deliverability and produce high ROI. Using a subdomain is one professional consideration; running a spam check to test the score is another worth taking further. There is no method that avoids the spam folder 100% of the time, but getting the above right establishes an effective, personalised channel between brand and member, and a serious foundation for marketing automation.