Email Deliverability – What Really Determines Inbox Engagement?

Do Internet service providers (ISPs) monitor clicks and the use of such words as “free” in subject lines to determine email deliverability? The answer to that question is no, according to a 2015 Email Evolution Conference (EEC) panel discussion held last month in Miami, FL, that included representatives from four of the largest ISPs. Here are highlights from the deliverability session with loads of specific recommendations for getting into the Gmail, AOL, Comcast, and inboxes.

Engagement Is Key, But Clicks Don’t Count

The final session at this year’s EEC featured four representatives of the largest ISPs fielding questions on email deliverability from email marketers. The ISP panel included:

  • Gmail (Sri Somanchi)
  • AOL (Paul Rock)
  • Comcast (Matthew Moleski)
  • (John Scarrow)

All four ISP representatives agreed that engagement is key to determining deliverability. But surprisingly, clicks are not one of the criteria ISPs use to measure engagement. Sure, if someone clicks on an email, they are demonstrating a level of engagement. But ISPs don’t measure clicks because not only is it a technological challenge, but also because ISPs consider the tracking of clicks to be a violation of user privacy.

Keep in mind that although ISPs aren’t looking at clicks to determine deliverability, click rates are still an important metric senders should track. Click rates provide a strong indication of whether or not your email content is relevant and engaging your subscribers – ultimately what the ISPs want.

Deliverability Is Personalized

What impact does using certain words such as “free” in subject lines have on deliverability? All of the ISP representatives were in agreement that a word, in and of itself, would not cause a deliverability problem. If a certain word tends to trigger a recipient to mark an email as spam or delete it without opening, however, the email would more readily end up in that person’s junk box. Therefore, it’s not the word that impacts deliverability, but rather a recipient’s reaction to the word.

This also demonstrates that deliverability is personalized, at least to a certain extent. If a recipient marks an email as spam, for example, emails from that sender may not make it to the individual’s inbox in the future. But that doesn’t mean emails from that sender will end up in the spam boxes of other recipients, too. That email, however, could end up in many junk folders if a lot of subscribers marked it as spam. In effect, the algorithms that determine deliverability are both a) personalized, so individuals can influence whether emails from a sender land in their own inbox or junk mail folder, and b) generalized, meaning behavior from the broad group of recipients will impact the ISP’s treatment of that email.

What Are the Seven Most Important Actions Impacting a Sender’s Deliverability?

So now that we know clicks and certain words don’t determine your email deliverability, then what factors do have an impact? All of the ISP representatives on the panel were very clear that a single factor never determines deliverability. Rather, it’s a combination of factors that indicate inbox engagement and ultimately affect a sender’s ability to have strong deliverability.

The following seven actions play a significant role in determining a user’s engagement with your email campaigns and, thus, deliverability, for specific recipients:

  1. Opening an email – Good

Thanks to some email clients that now download images by default, email opens have become a less important metric. But it’s still something most ISPs track.

  1. Deleting an email without opening it – Bad

This indicates recipients took a quick look at the subject line and sender address and determined that they weren’t interested in the email.

  1. Moving an email to a folder – Good

If recipients are taking the time to move messages around, they’re indicating a level of interest.

  1. Junking an email – Very bad

This is a strong indication that the recipient doesn’t want to receive the emails. In fact, AOL will automatically put email from that sender in the junk folder when recipients mark a sender’s email as spam twice.

  1. Moving an email from the junk folder to the inbox – Very good

This indicates that a recipient has an interest in receiving these emails. For AOL, it takes just one time of moving an email to the inbox to reset the previous spam classification.

  1. Adding a sender to the address book – Good

This indicates that the recipient is engaged with the sender.

  1. Replying to an email – Very good!

A reply is a strong indication that a recipient is engaged with the sender.

When it comes to an indication of email engagement, a reply to a message is a very strong sign. So what can marketers do to drive replies? One way is to create calls to action that actually reply to the email message. This may help to improve deliverability, especially on a segment of inactive users. Plus, it’s for this reason that using a no-reply email address isn’t a good practice for email marketers.

Keep in mind that regardless of how email engagement metrics impact deliverability, you must authenticate your emails and closely comply with CAN-SPAM regulations to help ensure optimum deliverability. For example, some of the basic CAN-SPAM regulations include promptly removing bounced email addresses from your database and efficiently processing spam complaints. Download our quick guide to the U.S. CAN-SPAM Act here.

In this article, we focused on deliverability issues that all four of these major ISPs were in agreement on at the EEC meetings. Check out the following links that delve into some of the deliverability issues unique to the individual ISPs: Gmail, AOL, Comcast, and

Got questions about how to optimize your email deliverability? FulcrumTech can help. Email us or give us a call at 215-489-9336 and get started today.

Other Articles You Might Like

Sign Up for NewsLever

Our free, monthly email newsletter

NewsLever is our free, monthly e-newsletter for B2B and B2C professionals who want to develop and implement powerful email-marketing campaigns that build relationships with prospects and customers.

  • This field is for validation purposes and should be left unchanged.

Privacy Policy|Learn More|Current Issue