The Effect of Email Engagement on Inbox Delivery

How much does your email inbox weigh? Chances are, if all your messages were converted into paper, you’d fell a forest every week. While most of us have adapted somewhat to the constant influx of emails, the barrage has left the medium damaged.

Internet service providers (ISPs) have always been concerned about keeping spam to a minimum. In fact, several of them have made changes to make the inbox valuable again. If you’re a marketer counting on reaching the inboxes of your customers, you’d better listen up.

Active and passive email recipients

ISPs have evolved over the past 10 years to 15 years from offering basic content filtering to actively monitoring senders’ reputations. Around 2001, several ISPs began adding “This is Spam” buttons to their users’ email systems to allow them to “vote” on the emails they receive. This user empowerment helped ISPs make the inbox more valuable for each user. Because of the “This is Spam” button, recipients could actively complain about email, sending future mailings from certain marketers directly to their spam folders.

In 2008 and 2009, ISPs have taken user-level voting to the next level. By clicking the “This is Spam” button, users are casting active votes that indicate their opinions about particular pieces of email.

But what about recipients’ passive reactions to emails? What about when recipients open emails but never turn on images or click? What if recipients ignore the emails entirely? ISPs have begun to recognize that these passive actions represent an implicit desire for these ignored emails to go away — meeting their goal of keeping user inboxes tidy. As a result, major ISPs such as Yahoo and Google’s Gmail are starting to block these emails, too.

Focus on engagement

For marketers, this means that gone are the days when you can email away willy-nilly while ignoring what’s happening on the other end. You need to monitor all of your campaigns for engagement, looking primarily for opens and clicks, which indicate that subscribers care about your email. If they don’t, over time the sum total of those ignoring you may outweigh the ones that are paying attention to you. If, in addition to this, some portion of your target audience continues to vote your email as spam, you could end up in the spam folder.

The bottom line: Opens and clicks help your deliverability; complaints and apathy hurt it.

Other industry experts have noted this trend. David Daniels of Forrester Research said the following in his June ’09 Email Marketing Forecast: “No longer will email marketers be able to dismiss critical tactics such as removing dormant subscribers from their mailing lists in order to improve message delivery.”

This isn’t just theory, by the way. I’ve seen it in action impacting significant revenues for a retail customer of ours. Like many retailers dealing with the recession-driven sales decline, this retailer began mailing deeper into its file to customers that hadn’t purchased in a few years, driving the balance of complaints up and engagement down. These imbalances lead to its emails being placed in the spam folder at Gmail.

The mailer identified and began mailing only to its most active file of customers who had opened or clicked in the past 60 days. This reduced complaints while increasing engagement. In a few weeks, emails began to hit the inbox again, leading to happy subscribers and a happier, wealthier retailer.

Chip House is vice president of industry and relationship marketing at ExactTarget, an Indianapolis-based email marketing services provider. Reach Chip at

Publish date: October 23, 2009 © 2020 Adweek, LLC. - All Rights Reserved and NOT FOR REPRINT