Email: Taking Email's Measure
During the last couple of years, we have developed a new measurement of inbox delivery. By monitoring marketing emails in spam and inbox folders of hundreds of thousands of actual consumers, we can now verify if email gets through to them and where it lands.
This should not be confused with what is often referred to as deliverability. As the word implies, deliverability only addresses the initial ability of the email to be delivered. That is, the sender receives verification that the email was transmitted from its servers/computers and was not immediately rejected by the receiving system.
That message may, however, be completely or partially rejected after evaluation from the receiving system, or it may be delivered to trash or spam folders rather than to the inboxes to which it was intended to be delivered. Thus, good deliverability does not guarantee anyone will actually see the email you sent, but bad deliverability guarantees much or all of the mail will not get through.
Until a couple of years ago, we relied solely on seed-based inbox delivery analytics. At the outset, this was a comprehensive solution where third-party monitoring companies would sign up for a multitude of random email addresses with different ISPs. By adding these addresses to the overall mix of subscribers—in some or all email deployments—the companies could use automated technology to log into the inboxes and see if the email had arrived, therefore giving the marketer a basic metric of inbox delivery success.
The accuracy of this approach was questioned by some because there were usually not enough of these "seeds" to give a comprehensive statistical view of success, but this method is still widely used today.
However, since ISPs have been enabling inboxes with both automated and user-defined personalization capabilities, the accuracy of the seed-based approach has waned. Instead, inbox delivery has been championed to combat this issue, giving a true picture of the consumer group being monitored and what is actually happening to the emails once they are sent.