Email Deliverability 101
The Best Email Deliverability Guide for Marketing. Ever.
In simplest terms, deliverability is the overall health of a sender’s email program. Before diving in, make sure you’re familiar with these common email marketing and deliverability terms.
AuthenticationA process that confirms to ISPs that you are who you say you are, and that your marketing automation platform is sending on your behalf. Common authentication methods include DMARC, SPF and DKIM
BounceAn email that cannot be delivered to the recipient’s email server. Generally divided into “hard” and “soft” bounces.
Hard BounceA permanent bounce from the server, usually because the intended address does not exist.
Soft BounceCould happen for a variety of reasons (e.g., full inbox, server outage). Unlike hard bounces, soft bounces are often temporary and fixable on the sender side.
Click RateNumber of clicks divided by number of emails delivered.
Click-Through Rate (aka Click-to-Open Rate)Number of clicks divided by number of emails opened.
Data HygieneThe overall quality of your email list and the associated data. Effective email strategy, and strong deliverability, always rests on a foundation of high quality lists with the right information.
Delivery RateThe percentage of emails that are delivered. Calculate it by dividing the number of emails delivered (total emails minus bounces) by the total number of emails sent.
Email Channel HealthMetrics like engagement, conversions, and even the ROI of your email program. You may be saying, “Isn’t that email strategy, not deliverability?” And you’re hitting on just the point we’re trying to make: you can’t separate solid email strategy from strong deliverability. And you shouldn’t try.
Inbox RateThe percentage of emails that are delivered to a non-SPAM folder. It can be estimated, but as a sender, you’ll never know the exact inbox rate.
Open RateNumber of emails opened divided by number of emails delivered.
Let’s start with a scene. A marketer walks into Act-On (or, more likely, joins us on Zoom) and meets with our Deliverability Team. They’re understandably eager to get started. They kick things off with what should be a simple question:
“What is my inbox rate?”
The Deliverability Team hesitates, knowing their answer is going to disappoint the marketer a little. They reply:
“We can narrow it down to a relatively tight estimate…but it will always be a mystery.”
The marketer looks confused. How can this be? They came here to get answers!
Well, today’s inbox is not what it used to be. For starters, what do you consider the inbox? The major ISPs (Inbox Service Providers such as Gmail, Yahoo! and Microsoft) all have their own way of filtering incoming emails according to the user’s expectations and customizations.
For instance, Google has its customizable tab system that includes categories like Inbox, Social, Updates and Promotions. Microsoft uses its own tab system divided into Focused Inbox, Promotions, Social, and Other. And of course, most major platforms offer users customization options to filter and route emails to their own subfolders.
Further, the ISPs use their own “bucketing” systems based on recipient behavior to route emails. These systems are opaque from a sender’s point of view–you can’t see what’s going on behind the curtain. A different message to the same group from the same sender, based upon content and reputation at the time of sending, might have a totally different placement.
As a sender, you don’t have visibility into any of this activity. You’ll only know whether your email was accepted or not. If an email is accepted, you can’t know whether it hit the “Inbox,” or a “Clutter” or “Promotions” folder where it’s less likely to be opened.
When you have a good sender’s reputation, your messages are more likely to hit the inbox. Likewise, a bad reputation will make emails bounce or hit the SPAM folder at a higher rate. Each ISP and filtering company puts different weight on different factors to determine a sender’s reputation.
Reputations can often be found on the postmaster page of the major ISPs. For instance, Google’s postmaster site rates domains on a 4-tier scale: bad, low, medium, high. Other ISPs have different scales and different reasons for affecting reputation. A good reputation is paramount to a sender, as it can help compensate for any deliverability issues that arise. It also leads to a higher ROI for emails. Good reputation is based on hard work, adherence to best practices, and versatility in a changing landscape. Data quality will have the largest impact on your reputation, followed by maintaining an engaged audience.
Visible to Sender / Negative Impact
Visible to Sender / Positive Impact
Spam complaint (at most major providers)
Hard bounce
Soft bounce (from reputation)
Repeated emails to unengaged recipient
Unauthenticated sends
Unformatted content
Hidden links
Bad or blocklisted links
Unsecured links
Opens
Clicks
Forwards
Replies
Authenticated sends
Double opt-in confirmation
Hidden from Sender / Negative Impact
Hidden from Sender / Positive Impact
Sending to a spam trap
Deleted messages
Ignored messages
Email views less than 1 second
User reports as abusive
Spammy content
User hitting the “This is spam” button
Email views greater than 1 second
User creates folder for email
Email promoted to better folder (e.g., Promotions to Inbox)
Moving a message from SPAM
Adding sender to address book
Starring/marking as important
We always recommend that email marketers consider deliverability as a core element of their email strategy, not an afterthought.
Remember that in Part 1 we discussed how engagement,performance, and overall channel health make a significant impact on deliverability. Addressing all the above elements in a comprehensive email marketing strategy will save endless time and frustration down the line.
Sending one-off emails without fitting them into a strategic framework is a recipe not just for low performing emails, but for getting your contentflagged as SPAM.
When and how often to send email is a key part of your strategy, and can have unforeseen consequences for your deliverability efforts. Consider the factors below when scheduling out your campaigns:
Email volumeYour email volume can have a drastic effect on deliverability and reputation. High volumes require a good reputation, lower volumes less so. Best-in-class senders can get away with sending millions of emails in under 20 minutes, whereas a low reputation sender may struggle to get 20,000 emails accepted and delivered to the inbox in 3 hours.
It’s also important to keep your sends consistent. Intermittent and erratic email volumes can tank your reputation and deliverability; consistent sending can bolster it.
TIP: To increase your volume without dinging your reputation, plan a slow, steady ramp up in volume. Start with a very low sending volume. Gradually double volume each week.
ISPs don't like dramatic spikes or plummets week-to-week. At most, you can increase consistency by 2 to 2.5 times before it begins to impact your deliverability.
Email cadenceThe cadence or frequency of emails should be a part of your overall email marketing strategy. Unsure how to determine the best cadence for your customers? The frequency of emails should be informed by the sales cycle of your product.
For example, if you have a 9-month sales cycle, a weekly email cadence is too frequent for your average customer.
Top- and middle-of- funnel recipients and current customer emails should be spaced out to avoid fatigue. In contrast, bottom-of-funnel prospects and newly onboarded customers (including active renewals) demand a higher cadence of emails to support and inform.
Daily
A few times a week
Weekly
A few times a month
Email fatigueWe’ve all been there: you sign up to receive emails from a potential vendor because you’re curious about a product, only to be inundated with all-too-frequent emails. It’s sort of the email marketing equivalent of agreeing to go out for coffee only to show up and find your date on bended knee with an engagement ring in hand. To avoid the SPAM reports and disengaged recipients that can result from email fatigue, devise a strategy for who you target and how you target them.
Fortunately, marketing automation offers tools for managing and preventing email fatigue. Set up email fatigue suppression rules to ensure that no single prospect receives more than your optimal number of emails within the timeframe that you define.
BONUS:
Clearly state why to open an emailCheck out this month’s promotional pricing
Use urgency with specificsConference registration ends Friday!
Use correct capitalizationTips for optimizing SEO on your website
Use emoji sparinglyHappy birthday! 🎂 We value your business!
Personalize the subject line to make it personalTiffany, seen our new blog on dental hygiene?
Mislead readers to trick them into openingIf you don’t buy, you’ll regret everything!
Use urgency without explanationHurry! Last chance, don’t miss it!
Use ALL caps or no capsSEO TIPS YOU CANNOT MISS
Use emoji throughout the subject line🥳🥳🥳Save 💸💸💸on 💻for your🎂🥳🥳
Personalize using confidential or sensitive informationTiffany, happy with your gum transplant?
