What Does Content Have To Do With Email Deliverability?


For 2022, Webbula is launching a series of blog posts about email deliverability topics. We have a variety of esteemed authors from the email industry lined up to participate. 

Previous Articles in the Deliverability Series
  • Subscriber Management: How to Start, Maintain, and Break Up by Elizabeth Jacobi. Read it.
  • Email Opt-Ins: It's All About Consent In the End by Matthew Vernhout. Read it here.
  • Email Authentication 101: What It Is And Why It Is Important For Brand Reputation by Yanna-Torry Aspraki. Read it here.
  • Why Blocklists Make Us Better Email Marketers by Andrew Kordek. Read it
  • IP Warming - Do It Right or Do It Twice by Amanda Jackson. Read it
    Email Deliverability and Subject Lines by Dela Quist. Read it
  • Email List Cleaning: 6 Tips For Mastering a Clean, Active Email List to Achieve High Deliverability by Jack Wrigley. Read it
  • Embrace Your Email Unsubscribe: 6 Recommendations to Optimize Your Unsubscribe Process for the Holiday Season By Mathias Ullrich. Read it
  • 9 Examples of Email Bounces and How to Analyze Them By LoriBeth Blair Read it
  • What are spam traps and can you actually avoid them. By Melissa Lambert. Read it

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I'm always telling my clients that email deliverability is like a puzzle. 

The entry-level to the email deliverability "game" is authenticating the sending domains (or sub-domains) with the proper SPF and DKIM records and implementing and monitoring DMARC. This step of the game will help you to build and maintain your sender reputation. 

Good email deliverability practices involve many more nuts and bolts. Key blocks in that puzzle include the domain reputation and the IP (or IPs) reputation. But today, I want to highlight a topic that may not get the proper attention: content, its reputation, and how it affects email deliverability. 

Image-only emails

One of the most significant missed opportunities regarding email design is using image-only emails. Designing image-only emails in Photoshop, Canva, or other design tools may be fast and easy, but marketers who use image-only emails are losing some exciting advantages.

For example, they don’t have the option to send hyper-personalized emails using dynamic content or to send responsive emails that anyone can view correctly using different screen sizes. If there is no live text in the email, image-only emails will look suspicious in some situations and might filter to spam, especially if sent to a corporation.

Even if image-only emails do not directly harm your deliverability, there are other reasons to avoid them:


The empty email syndrome

Viewing image-only emails on email clients that do not download images by default (MS Outlook on a desktop, for example) will look like "empty emails" without live text. 

Viewing empty emails is not a good experience. It often causes recipients to skip that email, delete it before reading (oops, negative points), or even report spam (number one reason for reporting spam: I don't recognize the sender). See picture below.



Another missed opportunity when using image-only emails is that these email messages are the same for everyone on the list. A block editor allows you to personalize every email block (on email platforms that support dynamic content) and send every person a different hyper-personalized message. 


On top of that, building image-only email messages will usually get less information (feedback to the ESP) about clicks. For example, when a customer clicks on an image-only email showing five products, the result will yield only one click. On the contrary, every unique link is different when building an email message using the block editor, which provides more data points about the customers and what they may like.


Image size

The time to load an email, especially on mobile devices, is time-sensitive and may lead to "email abandonment" if the email is not loaded fast enough. Images in the email message should be the same size as website images. As a rule of thumb, keep it around 100Kb. 


Responsive mobile-friendly design

Email messages consisting of images only are usually not mobile-friendly due to the variance in screen sizes, resolutions, aspect ratios, etc. This variance causes the email to be a less controlled experience which may lead to a bad user experience – by itself, a reason to unsubscribe or even worse.


Designing responsive emails is a breeze using the block editor on an email platform (or an external email editor like Stripo). It provides tools to ensure that your email is mobile and desktop friendly. 



Dark mode

Mobile devices usually automatically switch to dark mode from sunset to sunrise. Some images may look distorted in dark mode. Designing emails with the block editor will look fine when in dark mode.


Image-to-Text Ratio 

Some spam filters scan the email content, including words, and check the text-to-image ratio, especially when emailing to organizations.

In my experience, emails sent to corporations will get better inboxing when using fewer images and even text-only emails.


Spammy Words

When sending emails to Gmail, you can use spammy words as much as you like. Your emails will get to the inbox as long as your emails get a high engagement rate from users, but that's not the case when emailing organizations. Think of every organization as a small mailbox provider, and even when they're using Microsoft 365 (Office 365) or Google Workspace (Google Suite), the settings and policies are changeable per organization.



In some countries and regions, website accessibility is a requirement by law, but this is not (yet) true in email marketing. An email consisting of image-only is inaccessible to blind and visually impaired populations.


Another matter is that smart speakers and digital assistants (like Siri and Alexa) can only read the contents of an email if it has live text. For many people, email is like a data warehouse. I may not be a good example, but my online email archive contains emails from the 90s, and I rarely delete emails. Emails without live text do not allow indexing and searching for content.The solution for all those issues is to design emails using a block editor provided by your ESP or using an external email editor like Stripo.

Discrepancies between the HTML version and the text-only version

There are spam filters that don't like significant differences between the text-only version and the HTML version of the same email, and there are spam filters where it's less critical.

It's usually not something you need to worry about because most email platforms produce both text and HTML versions.


Standard HTML formatting for email

While both websites and emails use HTML, the editor designed for email differs from the website editor. I've encountered clients designing emails using Elementor, a well-known Editor for WordPress, and copying the HTML to the email platform. HTML created by Elementor (or other web editors) in the email platform may add unwanted add-ons (such as ActiveX, JavaScript, VBScript, and Java applets). That may harm deliverability or cause the email to be blocked (appear to be malicious or spam).


URL shorteners, redirections, domains, and filtering

Every link in the email message will affect the reputation of the email content.

Link shorteners such as Bit.ly, Rebrandly, TinyURL, and others URL shorteners suffer from low domain reputation.  Using a professional shortener that allows you to define your domain as a shortener is fine, though.


One more thing to consider is that email filters look for alignment in the URL/sending domain in both the header and the email body. The reputation of a domain can have an impact on whether or not your newsletter ends up in spam.One reason for this is because you control the domains that are linked to from each individual link within the newsletter, which may make it more likely they will receive low quality scores and end up being labeled as "spam."


In some cases, the reputation of the CDN and the tracking domains are the ones to blame. The ESP provides those domains, and you can't control it on many ESPs. If you can use branded links for tracking and image domains, you should. 


Sometimes email filters will do weird things like finding suspicious domains in the email text. For example: "this offer is only available to you. So what are you waiting for?"

Some filters will ignore the space and "think" that you are referring to the domain "you.so" which has a less reputable reputation, dragging down your content reputation.


Email size and attachments

Some attachments (PDF included) can arouse the suspicion of spam filters and cause email blocking or filtering emails to the junk or spam folders. Although sending an attachment using many email platforms is possible, this may not be a good idea. It is safer to send a link to your website and there to host the file.


HTML size

The size of the HTML is also essential. For those who use external email editors, be aware that Gmail trims messages if the HTML size exceeds 102KB (kilobytes). In this case, Gmail will display [Message clipped] notice and point you to click to view the entire message.


Images without Alt-Tags

The ALT Tag is an alternative text displayed when the Image is not displayed. Some spam filters will want to see this alt text. Also, as mentioned earlier, MS Outlook on desktop computers does not display images by default (you need to click to download pictures).

To summarize, there are many things to consider that can improve email deliverability and your email program in general. Some of them are related to the content of the email.

About the author


Sella Yoffe is a regular blog contributor for Webbula. 


Email Deliverability & Email Marketing Expert | Podcast host & Blogger @ CRM.BUZZ 

Helping companies with their email marketing programs by improving email deliverability, data, segmentation, content, & strategy.


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