The importance of subscriber engagement

Article author
Miguel Panayotty
  • Updated

Internet Service Providers (ISPs) like Gmail and Yahoo rely on subscriber engagement to determine your IP/domain reputation. The more disengaged your subscribers are with your emails, the more your deliverability will suffer. Poor engagement can lead to delivery delays or bulked mail.


How ISP engagement is measured

Every ISP calculates subscriber engagement differently and many use it to determine email inbox placement. ISPs don’t give specific metrics for determining engagement in order to protect subscriber inboxes from malicious senders. Based on various public forums and interviews with ISPs, the general consensus is the ISPs look at a number of factors to determine subscriber engagement:

  • Email opens
  • Email clicks
  • Ignoring emails
  • Deleting emails
  • Moving emails to a folder

ISPs use this data on a subscriber-by-subscriber basis to determine the subscriber’s engagement. Having many disengaged subscribers then leads to the ISP filters blocking or placing the email into the spam folder.


Engagement in WordFly

In WordFly we look at two metrics to calculate email campaign engagement: opens and clicks. The engagement rate of an individual campaign is calculated by taking your unique subscribers who clicked any link in your email divided by number of unique opens.



Unique subscribers who clicked (20) / Number of unique opens (100) = 20% campaign engagement rate

Campaign engagement rate


We’ve also created a unique formula to calculate subscriber engagement scores and ratings (stars) in WordFly. This data can help you better target the right subscriber with the right message.

Subscriber engagement rating


Increasing subscriber engagement

If campaign engagement is calculated by looking at opens and clicks, naturally the best way to increase engagement is by increasing opens and clicks. Put yourself in your subscribers’ shoes. What email content do they want to receive? How often do they want to receive it? When content isn’t engaging, you risk losing subscribers through the opt-out process or (worse) receiving an abuse complaint when the subscriber clicks “this is spam”. Focus on quality rather than quantity.


Focus on being relevant and targeted in your email marketing.

  • Collect subscriber preferences around content and frequency, then use this information to customize your emails
  • Personalize your emails with data fields and conditions
  • Include videos, animated gifs, and images that draw clicks from your subscribers

Run A/B campaign tests to see how small changes make a difference.

  • A/B test subject lines
  • A/B test from names
  • A/B test two emails

Send segmented campaigns.

  • Use WordFly’s segmentation feature
  • Provide offers to engaged subscribers
  • Turn engaged subscribers into brand ambassadors. Let them help spread your brand presence.


Reengaging disengaged subscribers

Equally harmful to your reputation is when subscribers ignore or delete your email. ISPs are trained to monitor even this non-action and it does play into your reputation score.

Conduct regular list audits every 3-4 months.

Remove subscribers who haven’t opened or clicked on your emails in over 6 months.

Send reengagement campaigns.

This should be done with small groups of disengaged subscribers (5% at a time).
Read more about reengagement campaigns


Reach out to your disengaged subscribers 2-3 times.

In the last campaign, consider telling the subscriber you will be removing their email address from your mailing list if no response is received. While this seems drastic, purging your list of disengaged subscribers will ultimately keep your emails delivering to your other “engaged” subscribers.