Email is a beloved channel. In fact, upwards of 90% of marketers rely on email to distribute content to customers.[1] And they should be—there are 244.5 million email users in the U.S. and over half check their personal email accounts more than 10 times a day.[2] At the end of the day, it’s a simple, cheap workhorse for driving revenue.

However, there is a dark side of email marketing. Spammers also send 60 billion (yes that’s with a “b,”) each day. To protect their customers, internet service providers (ISPs) have responded by implementing increasingly stricter spam filters. Google alone blocks 100 million spam messages each day on its Gmail platform.[3] So how can you ensure that your emails are viewed as legitimate, reach your customers and drive revenue? By considering Email Deliverability. While this is not the most glamorous of topics, it is one that every email marketer needs to understand and stay actively engaged with.

Many things go into Email Deliverability. Below we explore four of the top items in order of priority.

1) DNS and DMARC Setup

When setting up to start sending from a new e-mail service provider (ESP), several key steps are key to ensuring deliverability.

  • Establishing a sending domain – Create a subdomain to use for sending all of your emails. For example, or are two commonly used syntaxes. By creating a subdomain, you are establishing a separate reputation from the parent domain. This is important because it allows the recipients to identify the email as coming from you, but also keeps the reputation separate from your corporate/employee email so there is no unintended impacts.
  • Establishing Domain Name System (DNS) records – DNS records tie the IP address you are sending from to the sending domain. Your ESP should provide these records for your IT team. The DNS record will contain a Sender Policy Framework (SPF) which allows you to define which IP addresses can send for a particular domain. The SPF also includes a DomainsKeys Identified Mail or DKiM, which is effectively a digital signature to prove emails are not forged.
  • Domain-based Message Authentication, Reporting and Conformance (DMARC) setup – DMARC is the information that indicates what should happen if a message fails SPF and DKiM. While not always required, more and more ESPs are using it to determine if an organization is legitimate.

At Ascent360, we work with our clients to ensure that these records are set up correctly. Reach out to your Implementation Manager or Account Manager with any questions.

2) List Acquisition

Where you get your email addresses from is a great indicator of how well your emails will perform. Customers who provide their email at purchase or individuals who have raised their hands as interested in your product/service should be the majority of your list.

While different countries have different rules on who you can email (for example, CAN-SPAM in the U.S., CASL in Canada and GDPR in the EU), remember that just because you can email someone does not mean you should. List buys, web scraping, sweepstakes, and other list acquisition methods should be used at your own risk as they will likely lead to deliverability issues. Often within list acquisition methods that are less than reputable, you will encounter addresses planted by ISPs (known as “honeypots”) that are used to catch senders not following best practices.

3) List Engagement

As your email list ages, individuals who once wanted your emails will lose interest. This is when things can go off of the rails and lead to spam complaints, if you aren’t careful. Here are a few rules of thumb to ensure your emails are delivered to those who want them:

  • Send emails to new addresses as soon after acquisition as possible. Once an address has been on file for more than 30 days, only include it in future emails if the recipient has engaged with your emails in the past 12 months. This is ideally a click but an open counts too.
  • Ensure opting out of your emails is easy.  While no one wants their list to shrink, you want to make opting out of your emails easier than clicking on the “report as spam” button.
  • When emails approach the 12 months of no engagement point, make sure you have a campaign or play setup to help you cut the number of individuals you need to remove from your list. Ascent360 can help you implement this play. Addresses that have no activity after 12 months should be excluded from future emails.
  • One of the reasons for the 12-month engagement rule are Spam Traps. Spam Traps are emails that were once valid but have been abandoned (think of that old Hotmail address you used in college). Once an email address is considered abandoned or closed by an ISP they know that any email sent to it isn’t following best practices and is an indicator of spam.

4) Creative

Although creative plays a role in deliverability, its role has diminished over time. In early email days, ISPs heavily weighed the number of images vs. text content in an email. While they are relying less on this method, all-image emails are still associated with spammers so they are often routed to spam folders or blocked. According to best practices, you should include about two to twenty lines of text per image and include image descriptors in case your images are blocked.

It’s also important to be careful with subject lines since “spammy” subject lines can get you blocked. Do not use manipulative words and phrases that are designed to create unnecessary urgency. For example, “Now” should be omitted from most subject lines. Another good rule of thumb is to avoid exaggerated claims or promises that too good to be true. Subject lines that include “100%” “free” “bonus” or “instant” often land emails in the spam folder. The key with creative is testing – you can check your deliverability and continue to change your creative to ensure maximum engagement.

Email deliverability is an ongoing process

One of the challenges with deliverability is that the rules are constantly changing. So as a marketer this is something you will have to keep up on. But by following these four core ideas you can help ensure that your emails reach those you want and help drive revenue and the success of your marketing program. 

Did you know that you can send your emails directly through the Ascent360 platform? This means no more hassles of switching back and forth between your marketing tech stack and your ESP. We offer an intuitive email design editor to easily create engaging and effective templates and customized emails. See the Ascent360 data driven marketing platform in action. Request a demo of our platform below. 

Request a Demo


[1] [Content Marketing Institute, 2020

[2] Email Marketing Statistics and Facts by H. Tankovska, Feb 17, 2021 published on Statista

[3] “Gmail is now blocking 100 million more spam emails a day, thanks to TensorFlow,” Venture Beat, February 2019.





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