During our recent webinar, "How to Ace Email Deliverability," Acoustic Account Directors, Caroline Henno and Emmet O’Flaherty from the Professional Services team, fielded questions from attendees. Some of these queries were addressed live during the session, while others couldn't be tackled in real-time due to time constraints. In this article, our experts answer nine of the top questions we received.

1. How do IP address reputation and setup affect deliverability?

 

The types of emails you’re sending, and the volume (per day/per month), will define the type of infrastructure and number of IPs needed. The right set up will put you on the path to success.

After that’s established, the second step is the authentication of sending domains, which means that your sending domains have SPF, DKIM, and DMARC records configured. Domain authentication not only boosts trustworthiness with mailbox providers and your recipients, but also helps improve email deliverability.

Then comes the sender reputation, also known as IP reputation and sending domain reputation. Both are built over time and can be different across mailbox providers and ISPs. Your sender reputation will have an impact on email delivery and inbox placement.

Pro tip: Stick to the rules and make sure that everything is set up properly. Follow the best practices and recommendations to establish your reputation and maintain it across all mailbox providers. The more your subscribers are engaging with your emails, the better your sender reputation will be. Both are equally important for successful email deliverability.
 

2. Are there certain words or phrases that should be avoided to help deliverability?

 

Yes. There are buzzwords or keywords that will trigger spam filters. There is a list of some of these spam keywords in our help section. Note that no list is exhaustive since the keywords are constantly being updated.

When you schedule a campaign, Acoustic performs a health check that will provide you with a score from 0-5. The score is comprised of multiple categories, including spam words. Each identified spam word included in your email template will add towards your score. It is best to keep this score as low as possible. The Spam Score is generated using a ruleset from Apache SpamAssassin.

The rulesets are ever changing, so a particular set of phrases may not give you a high spam score on one send but may cause a higher score on another send. Therefore, it’s best to evaluate your wording consistently using both spam score and A/B testing to find out what works best for your business.

3. How important is it that your click-through domains match your sending domains?

 

Click-through domains are also called “custom” or “tracking” domains. These domains are uniquely branded and identify your company and brand.

When you add any links in your email campaigns, Acoustic uses the custom domain to re-write and track any clicks to your links.

Your custom domain aligns the hover links and URLs in the emails with your branding. This makes it easier for individual recipients to recognize and validate link branding before clicking. It provides recipients with the confidence that you are an authentic sender and that the email content is authorized.

Using a custom domain that matches your sending domain promotes brand consistency and trust, which helps with email deliverability. Custom domain tracking improves deliverability through bypassing email filters that often flag generic tracking links as spam. This ensures that emails are delivered to the intended recipients’ inboxes, increasing the chances of engagement and conversion.

4. For a large contact list (>1MM), will segmenting your sends by user engagement (e.g., sending to most active users first) help improve deliverability for those individual campaigns?

 

Yes, splitting your sends by user engagement and sending to your active subscribers first will give you the best chance of good email deliverability and avoid damaging your reputation. In general, you should avoid sending to inactive users as these contacts will garner the least amount of engagement and have the highest risk of impacting your deliverability.

Of course, the question remains: Do you want to continue sending to your inactive contacts? It’s important to weigh the risk versus reward when targeting these unengaged contacts. A large send to contacts who never open your emails may cause wider deliverability issues that can lead to bouncing even with your active contacts. There are multiple strategies you can adopt to navigate this, including changing of frequency, customizing content, or a launching a re-engagement campaign. These strategies must take into account your current infrastructure and sender reputation. It can be automated as an ongoing list hygiene mechanism.

5. If you’re’ adding a new sending domain and using an established sending IP is a “warm up” still required?

 

Because a sending domain reputation is easy to establish, especially if you already have a good IP reputation, you don’t need a defined warm up--but you should still introduce the sending domain slowly.

We wouldn’t advise starting by sending a high-volume campaign to a new audience using a brand-new sending domain. Instead, our recommendation is to start with a few small campaigns so that once the volume increases a little bit, you’ll be fine.

Pro tip: It’s always a good idea to let your customers know about any changes before they happen. An avid reader of your campaigns may identify changes to your sending domain and regard this as risky or as a phishing attempt. We recommend sending a notification detailing the changes to your sending domains and/or IPs with a request for your subscribers to add you to their safe sender's list or address book.
 

6. For sales/promotion type emails from the book industry what is a decent click rate?

 
Our 2024 Benchmark Report looks at aggregated data from 2023 for our customers’ sending emails. The report also does a deep dive into regional trends as well as industry trends. If you have industry-specific questions, we recommend downloading that benchmark report to see how your metrics may be matching up against industry averages.
 

7. In the education sector, when sending emails to people who work in schools, what’s the best way to prevent our emails getting blocked by the school’s security settings?

 

The same rules and best practices apply to the education sector and B2B email campaigns to optimize email deliverability.  

Make sure your sending domains are configured properly with SPF and DKIM. When universities or schools are using security vendors, they do often check SPF alignment to decide if an email should be accepted or rejected.

We recommend a strict policy for DMARC as this is also checked by security vendors— the stricter DMARC is, the higher the scoring. Make sure to also have one-click unsubscribe and SSL set up.

Your sender name and domain name are particularly important to help receivers recognize your emails. Setting up a landing page using the sending domain can also help. If subscribers search for this subdomain online, they will be directed to a landing page or re-directed to your website, offering another level of trust.

Finally, keep in mind the importance of data acquisition and list quality--it’s a key factor in maximizing B2B email deliverability. This means staying away from purchased or “rented” lists as much as possible to avoid hard bounces and spam traps, which will have a negative impact on your sender reputation.

Pro tip: Creating personalized and targeted content for specific audience segments is also crucial, not only to encourage opens and clicks but to avoid abuse complaints. From a design standpoint, ensure consistent branding across all email communications to establish a visible and trustworthy image for your company, and maintain a healthy text-to-image ratio. If the campaign is mostly imagery, it will bounce straight away.
 

8. Does email size affect deliverability?

 

According to Litmus, sending an email with an HTML size under 100KB has no impact on deliverability. Sending an email over 100KB could impact deliverability, but it may not be due to size alone and could be the result of the poor customer experience and engagement issues.

When creating and designing your emails, we recommend thinking holistically about your audience as you want to build the best subscriber experience. 

Your email file size can determine the bandwidth needed to download and see your email. Is your audience located in a region with slow internet? Do your subscribers mainly use mobile? If your subscriber can’t see your email, or it takes too long to load on mobile, it’s unlikely they’re going to engage or convert.

Also, we know that Gmail clips messages over a certain size, so subscribers might not be able to access all of your content which could result in missed clicks and frustration.

Lack of content engagement and accessibility will negatively affect your email deliverability, hence the importance of keeping emails under a certain size.

Pro tip: Generally, keeping emails under 75KB where possible will reduce deliverability risk.

 

9. How can you keep email lists clean?

 

List hygiene is the process of validating the data you acquire to ensure you have a clean list of contacts. This is an essential part of your marketing efforts. The main benefit of maintaining good list hygiene is improved email deliverability—a clean list can prevent hard bounces, inactive subscribers who are not engaging with your emails, spam traps, and abuse complaints.

To protect your sender reputation and keep a high level of engagement and revenue from your email campaigns, you must remove all contacts that are unengaged, fake, incorrect, or otherwise invalid.

Pro tips:

• Run your contacts through an email verification software to identify invalid addresses before sending campaigns.
• Identify inactive contacts. Try re-engaging them first. If they’re still unresponsive, delete them from your list. If they want to hear from you, they will re-subscribe.
• Review your data acquisition sources. Use double opt-in or data validation at time of sign up.
• Protect your webforms from bots by putting a real-time email validation in place such as CAPTCHA.
• Process bounces and abuse complaints to suppress them from future sends, and purge contacts who have unsubscribed from your list.
• Regularly audit your audience. Establish weekly/monthly check-ups to maintain a healthy and clean email list.
• Create list segments to gauge lists performance, identify where the engagement drop off is, and improve targeting and content relevance.

Clean email lists along backed by a strong email marketing strategy will keep your email engagement high and your unsubscribe and spam rates low.

If you have questions or want to discuss strategies for improving email deliverability with our team of experts, contact the Professional Services team at Acoustic.