Tangled and Cached: How Email Filters Affect a Marketer’s Life

August 07, 2018
Written by
Jacob Hansen
Opinions expressed by Twilio contributors are their own

Tangled and Cached: How Email Filters Affect a Marketer’s Life

Email was built to provide an easy-to-use electronic communication platform. Since the first legitimate message was sent in 1971 and the first spam message was sent in 1978, there has been an ongoing dance for email filters to determine which message is which.

Because of this, the delivery consultants here at SendGrid often hear a familiar question from the marketers we work with.
Is it fair that mailboxes such as Gmail and Yahoo! are placing our email in the spam folder even though recipients signed up to receive our emails?
From a universal human perspective, I would say no. From the email filters' perspective and its goals, I would say yes...completely fair. Confused yet?

The reason behind this dilemma is the same reason why we remind all marketers during consultations that email is an environment where marketers are essentially still considered a guest.

Even though your recipients have agreed to receive your email, it is still a privilege and not a right to land in their inbox.

Great-ish expectations

Major email inbox filters don’t want their users to feel overwhelmed with unwanted email landing in their inbox. And this is a fair point. If a user senses that their inbox is all junk email, they may drop that email address and try out another provider.

So, with that in mind, are you doing all you can to appeal to or hear from your user on what they want from your emails? Consider the following changes or improvements to your email program:
  • Optimize your signup flow - make sure that your sign up process is crystal clear and explains the frequency and types of content they will receive if they sign up for your email list.
  • Provide personalized message content - make sure you have segmented your email list so that you can provide relevant content for your users. For example, consider segmenting your highest engaged users and test sending them additional emails.
  • Keep an eye on your delivery and engagement metrics - adjust your email sending frequency if you notice a dip in engagement. 
  • Provide comprehensive unsubscribe/preference center options so that your recipients can customize their email experience to suit their expectations.
Keep digging into the elements above so you can be confident that you know what your users (and their representative filters) want.

Make it out to cache

As you monitor your email delivery and engagement rates, it's important to know all you can about updates to the major inbox providers as these updates often affect the metrics you see from the various inbox providers.

Gmail, and most recently, Yahoo! cache images in the attempt to make it easier to sift through and present all the mail it receives. Caching is a method to store data and web elements (such as images) so that it is faster to retrieve on subsequent page loads.

How does this update this affect data-driven strategies within marketing? Becuase images are used to track metrics such as clicks, this update can skew your engagement rates and not be as accurate as it previously was. What can you do to ensure your metrics are as accurate as possible?
If you haven’t already started paying closer attention to unique opens rather than aggregate opens, start now.
This can help you at least know the number of humans who were interested in your message and not the number of times that message was opened.

Caching makes it hard to trust the latter numbers and open rates because Google or Yahoo can technically cache an image for one recipient, yet display it for another recipient—therefore decreasing your unique open numbers as well.

To make sure this change isn’t affecting your email program and how you measure it, take a close look at your unique open rates before and after December 12th, 2017 and see if the trend has continued to decrease. If so, this may be the new normal to watch for.

If you send through SendGrid and want to dive into this and other delivery related discussions further, feel free to reach out to us. And for more email delivery best practices, read through SendGrid’s 2019 Deliverability Guide.

Until then...happy sending!

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