Email Sender Reputation: Decoded

As Benjamin Franklin once said, “It takes many good deeds to build a good reputation, and only one bad one to lose it.”

What exactly does reputation have to do with email? Sender reputation is a combination of factors that contribute to your status with mailbox providers as a good or undesirable sender. It’s a key factor in deliverability and an indicator of how likely your email campaigns are to be successfully delivered to subscribers’ inboxes (instead of landing in their junk folders or being blocked altogether).

Sender reputation is complex and dynamic, changing with each IP address you use and every campaign you send. Just one misstep can wreak havoc on your deliverability. Your email strategy may be impacted by one or several of the contributing factors that determine your sender reputation:

• Sending history: Also referred to as “permanence,” sending history is the length of time your brand has mailed from a specific IP address(es). Senders with long, established history at an IP address provides the mailbox provider with confidence that the sender and its messages are legitimate. In contrast, spammers change IP addresses often and quickly, making a limited sending history a risk factor. If you’ve changed ESPs recently or started sending from a new IP address, your sender reputation may be negatively impacted until you establish sufficient history.
• Sending volume: Both the amount and consistency of email you send matter. Regular patterns in volume indicate stability of activity and metrics. By contrast, large spikes in volume or erratic sending cadence can be problematic, as big swings could indicate additional legitimate email or spammy activity on the IP. This is a risk factor for all retailers as the holiday season approaches, and especially for seasonal retailers whose unusual selling patterns can cause a sudden increase in sending frequency.
• List quality: Nonexistent email addresses, also called “unknown users,” are addresses that result in a hard bounce back to the sender. Spam traps may be recycled from abandoned email addresses or set up solely to catch bad mailers. Mailing often to either type of address is a risk factor, as both unknown users and spam traps indicate a loose acquisition practice, something mailbox providers don’t take lightly. Tempted to mail that forgotten list you recently found? Think twice before you do, as your sender reputation could suffer.
• Complaints: This refers to the number of subscribers who have marked your email message as spam. Most mailbox providers have a “this is junk” (or similar) button within the inbox interface. This button is used by subscribers to directly report spammy messages that have slipped through the filtering process. Having a high volume of complaints is a direct indication that your mail is unwanted. Furthermore, because this feedback is coming directly from subscribers, many mailbox providers weigh this factor heavily.
• Subscriber engagement: Different from the way marketers define engagement, this indicates activity by the subscriber within the mailbox interface. While it’s a newer factor to sender reputation, it’s becoming increasingly important as mailbox providers incorporate more subscriber preferences into their filtering processes. Having a large portion of subscribers that don’t open or interact with your email consistently can negatively impact both your sender reputation and your response rates.

Tip: How do you know if you have a good or undesirable sender reputation? Sender Score is to sender reputation what a FICO score is to your credit rating. Similar to the way the banking industry determines a credit score for consumers, Sender Score provides a reputation score from zero to 100 (higher is better) for each of your IP addresses.

Even though Benjamin Franklin lived centuries before the first email was sent, he was spot on. It takes a lot of effort and consistency to earn a good sender reputation, and just a brief lapse in judgement to put your reputation on the line — or in the junk folder, in this case! Therefore, before you mail that list you just found or move to a new ESP platform, consider how your sender reputation may be impacted and proceed carefully.

Bonnie Malone leads the consulting, client training, and knowledge and editorial organization of Return Path, an email data solutions provider.