Since May we’ve been seeing more evidence that ISPs are gaining confidence in their use of engagement data. This is a trend we’ve watched closely, because bulk delivery decisions based on user behavior can make reaching the inbox even harder for lots of mailers.

Last week we got confirmation that engagement data has become a far more prominent component of deliverability at one major ISP: Yahoo.

We’d contacted Yahoo about a number of sender issues since seeing inbox placement rates drop by roughly 3% this summer, and poor user response was cited as a cause of bulking. More recently, the company warned that as it improves its ability to analyze behavior to determine what users want delivered to their inboxes, some senders — even responsible mailers — may face deliverability challenges.

While Yahoo’s increased use of engagement metrics to block email is new, the company has made no secret of its intent to use more sophisticated metrics to filter email. And it’s not alone. Microsoft has long incorporated Hotmail user response (Junk/Not Junk, Opens/Delete No Open) in its filtering; Gmail prioritizes email with high engagement into the Priority Inbox. As top ISPs compete for customers, improving their inbox experience will continue to be a primary focus. It’s important to follow this development because:

What’s now a relatively minor component of email deliverability decisions by handful of receivers may become a far more prominent factor in determining whether vital marketing campaigns reach the inbox.

Deliverability monitoring becomes much more complicated in an environment where individual users’ interaction with messages helps determine inbox placement.

Two things can help you reach the inbox as engagement becomes a factor:

First and foremost, keep focusing on delivering a great email user experience. The same practices that maintain your sender reputation – well segmented lists, authentication, active brand protection – can help prevent poor engagement from undermining your deliverability and campaign performance. But you might want to step it up. The bar has really been raised and marketers who are squeaking by with high-volume, low-response programs are going to start to lose out, at least with Yahoo.

Second, use versatile deliverability monitoring approaches to establish performance across the receiver landscape. Ideally, this means using panel data — metrics showing actual recipients’ engagement with real email messages as well as the actual inbox placement for those exact users – to enhance the deliverability picture that seedlist data provide. Even as the biggest ISPs explore how user behavior should affect inbox placement, most will continue to rely on the reputation factors that have always influenced inbox placement rates.

Thanks to the Return Path Email Intelligence Group, and specifically Christine Borgia and Melinda Plemel, for their work to confirm this key industry development. I couldn’t have written this column without them.

By George Bilbrey

George Bilbrey is president of Return Path and founder of the industry’s first deliverability service provider, Assurance Systems, which merged with Return Path in 2003.

Read this article on the MediaPost.com website.