A Question of Reputation

It's the one factor that can instantly make or break any email campaign. Everyone knows that it's important. After all, people will only open and click emails they see. Yet, testing email deliverability is surprisingly difficult. There are plenty of tools out there that claim to test the inbox placement of email campaigns, but few of them are reliable.

Most marketers follow a few basic guidelines for getting an email campaign into the inbox but are fully aware that there is a lot more to deliverability than that. The algorithms that separate good emails from junk emails are incredibly complicated, being ultimately based on a set of highly technical industry standards. Much like SEO, only the people who control the algorithms know exactly what is in them.

We have a vague idea of what spam filters look for because security firms tell us enough to get normal corporate and personal email delivered. Much of the guidance they publish is around DNS settings and email server configuration. The DNS configuration still applies when setting up an ESP or Marketing Automation platform, and also when changing the domains you use to send emails.

As if this wasn't complicated enough, every email actually has two from addresses. The one you see and the one the server sees are different. The server address is variously called the bounceback address, the envelope address or return-path address. It is the email address of the server that sent the email. Most high-end ESPs and Marketing Automation Platforms allow you to brand this address to enhance deliverability.

This is not the same as the email address you see in your mail client. Most marketing platforms allow you to send the email from pretty much any email address. You can easily send an email from your CEO's email address using any ESP. This doesn't mean that the email is literally sent from your CEO's mailbox. Instead, the server uses its own mailbox and its own email address which typically don't change from campaign to campaign.

There is a reason for that. Deliverability is mostly about the reputation of your email server. ESPs judge this based on the reputation of the server's email domain and of the server's IP address. The various DNS records that you create for every email domain are about proving your identity to receiving servers. There are three types of DNS record used for email deliverability:

• SPF: which is simply a list of servers permitted to send email from a domain. Strictly speaking, this is only used to verify the server address, but in practice, the from address you see is checked too.
• DKIM: which is about proving the email came from your server. DKIM digitally signs emails with an encryption key that is published to DNS for verification.
• DMARC: which is about proving the server address and the standard from address match. This is a newer standard designed to prevent phishing emails.

None of these will fix a bad sender reputation or remove you from blacklists. Not having them is a red flag which does increase your chances of going to spam or quarantine folders. The only way to get a good sender reputation is not to act in the same way as a spammer. Reputation is the big thing in deliverability but ultimately boils down to the types of emails you send, the frequency you send them, and who is receiving them.

Of these three factors, content is the least important but also the best understood. A good balance of text to images, strong copy, and legible text go a long way to keeping you off blacklists. Don't ignore the human factor though. It is not just algorithms that determine spammy content. Human spam complaints are vastly more important. A spam complaint can you see you blacklisted instantly.

The best way to avoid spam complaints is through good data hygiene. This also avoids the other automatic blacklist trigger: spam traps. Spam traps are old and unused email addresses that the blacklist companies have taken over for spam monitoring. As they are old accounts, the theory goes that no legitimate sender should be sending real emails to them. Only spammers send to any old account. Legitimate senders are supposed to stop sending after the email bounces a couple of times. You should update your lists accordingly because most marketing automation platforms don't automatically block contacts that bounce repeatedly.

In a similar vein, remove contacts who don't respond for more than a year from your distribution lists. Inactivity can be an indicator that someone has left, so don't keep old sending to opt-ins forever. A clear data archiving strategy can solve many issues, including poor deliverability.

Finally, there is the issue of how often you send emails. This is the most difficult factor to control but is still incredibly important. Most email servers follow a predictable sending pattern with consistent volumes of emails being sent over a monthly or quarterly basis. Any peaks and troughs follow a regular pattern. This is true for marketing email as well as for business email. Wild swings in the number and frequency of emails sent are typically associated with spammers. As such, email security vendors monitor the activity of each email server closely. Strange behaviour is often a cause for detailed investigation and potential blacklisting.

Most ESPs manage their sender reputation very carefully paying close attention to blacklists and sending volumes. Larger senders typically have a dedicated IP. There are advantages to this, as it prevents you from being blocked by someone else's bad behaviour. The downside is that a dedicated IP requires monitoring and management. Reputation needs to be protected, blacklists need to be monitored, and campaign schedules need to be monitored to avoid irregular spikes in activity. Unfortunately, Marketing Operations teams typically don't do all this, even when they are expected to, meaning that deliverability only gets discussed when something goes wrong.