When it comes to email deliverability, sender reputation is kind of a big deal. And by “kind of” we mean “very, very much”. Whether you land in the inbox or in spam is determined by the recipient’s mailbox provider (Gmail, Outlook, etc.), and the mailbox providers use sender reputation to determine whether you’re trustworthy enough to go to the inbox.
Much like a credit score, your sender reputation is a multi-faceted score based on several factors, including your history of positive and negative behaviors reported from multiple sources. And like a credit score, our sender reputation is ever-changing and could take some time to build.
IP vs. Domain Reputation
There are two main types of reputation that mailbox providers (MBPs) use to determine whether your emails make it to the inbox: IP reputation and domain reputation.
Tied to a particular server address, IP reputation uses the address as a unique identifier to determine whether a sender is trustworthy. Since shared IPs can suffer from the bad actions of other senders using the IP, high-volume senders often send from dedicated IP addresses. It is also important that companies send their marketing and transactional emails on separate IPs.
As MBPs have become more sophisticated over the past several years, Domain reputation has become much more important. Since this reputation is tied to your sending domain (@yourdomain.com), it can follow you even if you switch IPs or email service providers (ESPs). So incorporating good sending practices will continue to be more important as domain reputation is adopted more widely.
What Influences Sender Reputation?
While IP and domain reputation are the most prominent, it’s important to note that many other factors like content, URLs/links in the body of your email, and countless other factors can also impact sender reputation.
In fact, there are literally hundreds of factors that go into determining if your message will be delivered to the inboxes of your recipients or not. This includes the ever-changing algorithms driven by data points that each MBP deems important. It’s not as simple as one number like a sender score to rule everything.
Don’t worry, though. We won’t get into every single factor. Instead, we’ll provide a high-level overview of the key factors affecting sender reputation: those which can be controlled by senders, as well as what indicators can be used to know if you’re on the right track with your email program. Much like learning to drive a car, we must first understand the things we can move and steer, as well as how to read feedback signals like the dials and meters on a car’s dashboard.
Generally, there are four main indicators of the health of your sender reputation: Negative Reactions from Recipients, Spam Traps, Blocklistings and Bounce Rates.
Negative Reactions from Recipients
User Complaints, sometimes referred to as “Marked as Spam” Rates, are very heavily weighted by MBPs since they are such a clear indication, directly from the user that the email is not wanted. User complaints can come from recipients even if they’ve opted in to hear from you, so pay close attention to your complaint rates, and deal with them immediately to prevent damage to your sender reputation.
And much like spam reports, unsubscribes are a sign that recipients are looking to get off the ride. Make the unsubscribe process easy because if users aren’t able to unsubscribe, they will likely mark your email as spam instead. Also, consider allowing users to tell you the reason they are unsubscribing, so you can modify your program accordingly. Understanding all of this can help you retain potential future customers, instead of seeing them continue to unsubscribe or mark your emails as spam quickly after signing up.
Spam Trap Hits
The number and type of spam traps you send to is another strong indicator of whether or not your sender reputation is in good shape. These email addresses are used by MBPs and anti-spam filtering technologies to identify senders with problematic list collection and/or maintenance practices. There are three main types:
Typo traps occur when someone mistypes their email address. These are used to highlight problems with list collection. Senders can improve the amount of typo traps entering their list by asking subscribers to type their email address twice, or by implementing Kickbox’s real-time email verification api on their signup forms.
Recycled traps are email addresses that were once active, but have since been disabled by the user or closed by the MBP due to inactivity. MBPs will deliver a bounce message saying something such as “this address is inactive” to any sender who tries to contact that address for AT LEAST 12 months. So here, the trap is used to detect issues with list management. If you’re hitting recycled traps, the best way to deal with them is by targeting only active recipients.
A pristine trap can be the most damaging to your sender reputation. These have never been used to sign up for anything. Simply planted on the internet waiting for some bot — or intern — to find them and start sending to them. Here, the goal of the spam trap is to identify people who are truly sending spam… that is, sending to addresses that have never given you permission to send emails to them. If you’re collecting an opt-in from all of your recipients (like you should be!) and are still hitting pristine traps, it’s time to take a close look at your list collection practices and ensure all submission forms are locked down with a CAPTCHA, or one of the alternate forms of protection available to prevent bot signups.
Our Kickbox Deliverability Suite can help you identify issues with list collection and management by harnessing the power of our spam trap monitoring and real-time alerting features. Know right away if you’re hitting spam traps within our extensive network.
Get your free consultation today to see if the Deliverability Suite is right for you.
Blocklists are real-time lists used by MBPs to identify IP addresses and domains that are known to send spam. They are normally triggered by spam trap hits, user complaints, manual abuse reports, or a mix of these.
The main thing to be mindful of with blocklists is that they all do not carry the same weight. Spamhaus, Spamcop, and a few others are the major ones, but there are literally hundreds of blocklists out there that don’t necessarily doom a sender to the spam folder with every MBP.
So it’s important to understand which destinations you send to the most. If you’re a B2C sender, for example, a listing by SORBS might not have a direct impact on deliverability. Whereas if you’re a B2B sender, the SORBS listing could be factored in by many of the corporate domains you’re sending to, impacting inbox placement with recipients at those domains.
When an email is not successfully delivered to the recipient’s mail server, it is considered a “bounce”. We’ll cover this in more detail in the next episode, but for now, it’s important to know that there are hard and soft bounces.
Hard bounces occur for permanent reasons like an email address not existing. Soft bounces usually occur for temporary reasons, like the recipient’s mailbox being full, the recipient’s mail server having an outage, or the MBP is blocking a particular email due to sender reputation or issues with the content.
Now that we know what indicators to use as a measure of our deliverability, let’s dig into what we can actually control in order to improve our sender reputation, allowing MBPs to have higher confidence in our legitimacy as an email sender. The main factors to focus on are:
List collection and management
When it comes to email marketing, our contacts are our currency, and quality over quantity is key. Practicing good email list management involves collecting email addresses from opt-in sources only, setting clear expectations with subscribers, and segmenting out your most-engaged subscribers from your less-engaged ones. And of course, never buying, renting, or scraping lists.
Volume & timing of messaging
As email practitioners, we often want to send the most amount of mail possible while remaining relevant and keeping our subscribers delighted. But if we overdo it, we can drive our email recipients away and potentially ding our sender reputation.
When it comes to sending volume and timing, setting expectations is the foundation. For example, if you have a list of subscribers that signed up for a weekly email newsletter, suddenly emailing them daily might lead to negative forms of engagement including spam complaints, unsubscribes or low open/click rates. All of these are bad for deliverability. Setting expectations and sticking to them, or letting your subscribers know when you’re making a change, can help keep negative recipient reactions to a minimum.
Content of your emails
While the days of a single trigger word like “free” ruining your reputation are over, the content of your emails still matters! It can influence your recipient’s engagement, and in turn, your sender reputation. This comes down to a few key factors within the actual subject matter of your emails:
- Relevance – does your recipient actually want this?
- Spammy-ness of your subject lines or content
- Image/text ratio
- link/URL reputation – using shorteners can often be harmful since these are often abused by spammers and fraudsters
- Plain text combined with HTML
Lastly, authentication can influence the level of confidence that MBPs have in you as a legitimate sender. Authentication methods, including SPF and DKIM, are intended to prove that the emails you send are actually coming from you.
Once SPF and DKIM have been implemented, an additional authentication standard called DMARC allows domain owners to monitor authentication failures on their domain, which can help them identify issues with spoofing or phishing emails being sent by fraudsters. It also allows them to inform MBPs how they would like their emails to be treated if they don’t successfully pass authentication checks: to either send them to the spam folder, or block them completely.
And then most recently, a new method of brand identification and email authentication has been introduced called BIMI (Brand Indicators for Message Identification). BIMI leverages the work an organization has put into deploying DMARC protection by bringing brand logos to the customer’s inbox.
We won’t go any further into authentication today, because it can get really technical, really quickly. Not to worry, we’ll explain these in more detail in a future episode.
There are a head-spinning number of factors that influence your sender reputation. Thanks to machine learning, artificial intelligence, and the new malicious email threats emerging every single day, deliverability is a moving target. And it doesn’t help that these ever-changing algorithms are kept secret by mailbox providers.
But that doesn’t mean we can’t understand the basics and use that knowledge to take control as an email marketer. Empowered with this understanding of sender reputation, we can be more confident in staying in good standing with mailbox providers and subscribers alike.
Stay tuned for the next episode
In our next episode, we’ll cover email metrics – how to measure your deliverability and gain actionable insights into important things like your sender reputation – with a special guest speaker!
Not caught up on the series? Check out our last episode, “What is Email Deliverability,” to find out how deliverability affects your email program, your relationship w/ inbox providers, your sending platform & your subscribers.
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