Deliverability changed on April 6. On that day, Google changed their deliverability filter algorithms and, similar to how changes to their search ranking algorithms affect SEO, this change affected a number of our customers – some for the better and some for the worse.

Unfortunately, the changes weren’t just disruptive for marketers. They were troublesome for recipients by creating an abnormally high level of false positives – messages that were incorrectly filtered to the bulk folder. Google has acknowledged this problem and has hence rolled back some of the changes. Subsequently, this has improved the email marketing metrics for many of our customers but not all.

So What's Going On Here?!

Google, like all ISPs, want to improve the email reading and writing experience for the customers. Part of that means ensuring that the Gmail inbox stays clean with relevant and interesting messages and filtering other messages elsewhere. Google, of course, does not spell out the specific weightings of the filtering attributes – nor should they. But, when we started seeing discrepancies in metrics with Gmail, we dug deep into the issues to assess what has changed. We developed a deeper set of deliverability monitoring tools. We ran through an extensive set of controlled tests. We evaluated everything from domain authentication protocols to message content. We tied in the relevant deliverability experts at Google and at Return Path, a third party deliverability consultancy.

The end story is that reputation and recipient engagement matters more than before and marketers that did well in these areas will continue to see great results. Marketers who didn’t have a strong relationship with their Gmail subscribers will not do as well.

What You Can Do

There is no magic bullet, but here are three things that Bronto users can do to ensure that they are positioned as well as possible for strong deliverability:

  1. Setup a private domain. A private domain lets you control your own reputation and not have it diluted by others. In practice, this would mean your messages’ sending domain and content URLs would look more like than This has the additional benefits of providing a more complete branding experience and letting you apply DKIM (Domain Keys Identified Mail) to your own domain. To be more exhaustive, consider moving your message’s images to alternative locations to change their underlying URLs.
  2. Engage your audience. Google is increasingly using engagement metrics to determine inbox deliverability. Recipients clicking “Report spam” and “Not Spam” for your message significantly feed into those metrics, along with if they open the message, display images by default, click on links, etc. The exact formula is and will always be unclear. However, what is clear is that marketers who have engaged audiences will continue to see good results with Gmail. Also, we suspect that Priority Inbox will increasingly play a factor in this.
  3. Segment between Engaged and Unengaged. Your marketing effectiveness with your unengaged contacts affects the results with your engaged contacts. Segment the two groups from each other and treat them differently. If you cannot re-engage these contacts, stop marketing to them because they are a “This is a spam” event waiting to happen. Unresponsive contacts hurt your reputation and hence will affect your overall deliverability to Gmail.

Follow The Best Practices

Inbox filtering and deliverability, at first, can seem like voodoo magic. But, the spirit of what it takes for great deliverability is simple and breaks down into three simple things:

  • Own your reputation so you get credit for your engaged audience and not have your strong results diluted by others.
  • Establish a strong relationship with your audience by starting with solid and clear permission-based signup policies. Think less about what’s legal and more about what’s obvious.
  • Engage your audience by sending your recipients messages that are interesting to them. Your recipients prove this to Google by not reporting it as spam, reporting it as “not spam” if it inadvertently lands in the bulk folders, displaying the images, prioritizing it in their inbox, etc. This proof feeds directly into Google’s filtering algorithms.

The trend in deliverability is clear -- domain-based reputation and engagement are mattering more than before. Follow the steps above and see where it goes. Like with SEO, there are no engineering short cuts. Strong deliverability ties directly to strong marketing practices and strategies. At Bronto, we provide the platform and people to make you the best that you can be – but ultimately, deliverability (like security) is a shared responsibility and hence varies considerably among clients.

To stay informed of deliverability changes like these, we encourage you to keep tabs on the announcement section on the Home tab of the application. You can also follow Bronto Status on twitter for real-time updates on deliverability and system performance.

We are here to help. Implementing these changes should be fairly straightforward and Bronto Support is ready to walk you through any of the features should you need help. Just give us a call (919-595-2500) or submit a case from within the application and we’ll be ready to get you started on improving your Gmail deliverability.

Joe Colopy
CEO of Bronto Software