Email marketing continues to be one of the most popular digital marketing tools. This is due to its great versatility and ability to foster connection with users. But it is also true that many users associate email marketing with spam. We delete dozens of spam emails daily and many end up labeled as spam by email providers themselves. On the other hand, we do appreciate the usefulness of those emails that interest us and are genuinely helpful. So how do you ensure your email marketing is useful, effective and doesn’t end up being flagged as spam?
There are two dimensions to the spam problem – the technical dimension and the content dimension. Users can consider certain emails as spam for various reasons – because they are not interested in the topic because they do not find the content useful, etc. But for these emails to reach inboxes and not end up in spam, they first have to go through the filters of email service providers (ESP). Let’s see what email delivery capacity depends on and how to improve it.
What does email deliverability depend on?
The email marketing deliverability depends on the following factors:
One of the key factors that email service providers will look at when determining if an email is spam is the sender’s IP address. If a specific IP address has received a lot of complaints in the past, email from that address is more likely to be identified as spam. Sometimes emails from an IP with a bad reputation may not be accepted at all by the receiving server and the sender will get a bounce notification.
The reputation of a domain refers to the score that ESPs give it. This score helps email providers decide whether or not something passes through to users’ inboxes.
Each email service provider may score a domain differently, but factors ESPs typically consider include:
- Number of emails from this domain and IP that were classified as spam
- Number of emails from this domain that are sent to spam traps (fictitious email addresses that ESPs use to identify senders who are not following best practices)
- Number of inactive or non-existent users in the contact list
- Presence of the domain in blacklists
You can check the reputation of your domain and your IP in Talos Intelligence and Sender Score.
Domain authentication with SPF, DKIM and DMARC
Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM) and Domain-based Message Authentication, Reporting and Conformance (DMARC) are email authentication protocols that certify that the sender is sending a secure email.
They are a key component of deliverability, and their configuration depends on the email service provider you use.
Bounce rate or return rate refers to the percentage of emails that return to the sender’s server because they could not be delivered to the recipient. An email can bounce for various reasons such as:
- invalid or non-existent email addresses (hard bounce)
- temporary recipient server failures, full recipient inbox, not enough space on recipient server (soft bounce)
ESPs maintain sophisticated anti-spam filters that identify patterns in content or words and phrases that spammers often use. Each ESP has different lists of words that it considers spam, but they all focus on monitoring the subject of the email, the attachments, the header and the body of the sent email.
In general, it is recommended to avoid words related to health and pharmacy (unless your company is in this industry), exclamation marks, words in capital letters, and currency symbols.
It is clear that content plays a key role when classifying an email as spam. But it’s not enough to just avoid words typically associated with spam emails. The most substantial effect influencing deliverability is user interaction.
If the content is not high-quality, users are less likely to engage with it and may even report the emails as spam.
What’s more, when deciding which emails to mark as spam, Gmail’s algorithms for example place great emphasis on individual user actions in the inbox. Because one man’s spam is another man’s principal inbox messages.
Some examples of user actions that Gmail considers include:
Messages marked as spam
Messages deleted without being read
Messages moved to Promotions
Spam reports or complaints
How to improve email deliverability?
Don’t buy or rent contact lists
It is a popular practice to increase the number of contacts but it is not exactly the most recommended one. Keep in mind that contacts acquired in this way have not given their direct consent, so it is very likely that they will not be interested in your content. This could lead to them not reading your emails or worse yet – marking them as spam. In such a scenario, your reputation as a sender would be damaged and ESPs would be much more likely to start treating your campaigns as spam.
Clean contact lists and don’t send emails that bounce
Bounce rates are important indicators because recipients’ email providers can interpret them negatively: as if the contact list has been purchased or as if it’s not being cleaned and updated regularly.
Therefore, you must periodically review the bounce rates of your email marketing campaigns to remove contacts that bounce off and follow the best practices of email marketing. You can remove contacts that:
Haven’t opened any mail
Haven’t had any interaction with your content, services or products for more than 1 year
Using a list of contacts who actually open and read your emails will help maintain your reputation as a sender and will also save you the extra money per contact.
Ensure easy unsubscribing
Although no one wants their contacts to unsubscribe from email marketing campaigns, it could actually be a positive thing. Instead of never opening your emails or marking them as spam (which would damage your reputation as a sender), a simple “unsubscribe” would help both the contact to not receive content that does not interest them, and you to maintain a list of contacts that really have lead potential.
Ensuring easy unsubscribing is also a legal issue. According to the GDPR, the process must be facilitated in case users change their minds and opt out of receiving emails. If a marketing email doesn’t have an unsubscribe option or is sent to someone who never subscribed, it’s violating the GDPR.
The best practice is to place a visible unsubscribe button in the footer of the messages and make the process as easy as possible. That is, not force the user to follow several steps until they can formalize the unsupscription.
Don’t include videos, unoptimized images or attached files
Many email providers block images by default and don’t allow the ability to view rich media or embedded videos.
Make sure your emails can be understood even with images blocked. In this sense, it is advisable to use alt text. So in case an image is not displayed, users will see descriptive text instead of a blank block.
On the other hand, images must be optimized for the web so they don’t take long to load if their display is enabled. As a general rule, images should be no larger than 300kb and 600px wide.
And if you want to include videos, it is advisable to put a link or button that clearly indicates to users that they will be redirected to watch the video.
The header, body, images, and links of your emails are relevant factors in determining whether an email is spam, promotional, social, or inbox. But while content is still key to ESP filters, the level of enforcement of those filters increasingly depends on the sender’s reputation and performance. That is, if your subscribers interact with your emails (they open and read them), this would have more weight when it comes to passing spam filters. This is because email providers count on the behavior of the users to personalize email services and improve them.
To guarantee active and positive participation of the users, it is advisable to regularly clean the list of subscribers and remove those who never interact. It is also recommended to use a different engagement strategy for passive subscribers or contacts that show lower levels of engagement. Using a different email cadence with passive and active subscribers will decrease the risk that ESP like Gmail will treat your future messages as spam.
Avoid sending bulk campaigns
If you send email marketing campaigns to new contact lists, it is better to do it in phases. Mass campaigns tend to turn on ESPs’ red flags. What’s more, sometimes an email may not reach an inbox simply because a large volume is being sent to the same server at the same time. If you send the same email to too many contacts on a domain that uses speed controls, your emails may not be delivered.
For this reason, phasing emails can increase your deliverability. Contacts can also be divided into shorter lists to prevent ESPs from detecting that you’re sending bulk emails. This is especially useful if your domain does not have an established reputation.
Register specific subdomain for email marketing
It’s possible to register a subdomain with the sole purpose of sending email marketing campaigns. This way, you can independently build your reputation and leave a good impression on email providers through a proper and regular email cadence.
Set up authentication protocols
As previously mentioned, authentication protocols are one way ESPs verify email senders and prevent hackers and spammers from reaching inboxes. ESPs are much more likely to classify emails that fail authentication as suspicious or spam. That is why it is highly recommended to ensure the correct authentication of your emails with SPF, DKIM or DMARC.