Email: The 99% Delivery Myth

You’ve just sent your eblast about your biggest sale of the year. You refresh your stats and see:99.97% delivered. All that hard work planning, coming up with that killer subject line, discussing the proper creativity, etc… Now we wait…

The day passes and your open rate is a dismal 5%. Enter the marketer’s death spiral;  How can this be? Was the subject line that bad? Should we have split-tested more lines? More meeting?

Or maybe your clients never even saw the email…

The deliverability stats means the email was indeed sent out and received by the user and the open rate tells you how many opened it ( rudimentary I know), but there’s no stat that tells you if they saw the email OR that the email went directly to spam..

Sending Reputation: Your email credit score

Just like a bank would check a credit score before giving credit, a mailbox checks the “sending reputation.”  Below is a list of sites that can give an overall view of your sending credit score:


3 main delivery factor: The email FICO composition

Similarly to SEO, the Mailbox uses different weighted factors to determine what gets in and what doesn’t, those are; a) the source, b)the reputation, and finally c) the content.


The first factor the mailbox uses to determine to let the email into the inbox or not is the source. Therefore the domain/IP are the first thing to inspect. There are about  300 publicly available blacklists but only a few of them are seen as true authorities on the matter

They are split into 2 categories; IP and domain based

IP Blacklist

IP addresses are queried in real-time to determine if the source is trustworthy.  Here is a list of widely used blacklist:

Domain Blacklist

Parallel to the IP blacklist ,this list looks at the links within the email (including redirect) to determine  the domain. Here is the list of the domain blacklist you can use to evaluate your domain and sending ability


This component is algorithmic based and leverages million of points. That being said those points can be categorised in 5 different components; Complaints, spam traps, the message composition, send volume and blacklist(mentioned above)

Complaints have the biggest impact so minimising this aspect would be best. For Gmail you can check your level spam and complaints using the Google postmaster tools


Content is not just limited to the messaging within the email. Filtering technology is advanced to the point that the whole email is analysed before deciding if its let through. Here is the non-exhaustive list of what is analysed:

  • Header
  • Footer
  • Code
  • HTML markup
  • Images
  • Text color
  • Timestamp
  • URLs
  • Subject line,
  • Text-to-image ratio
  • Language
  • Attachments

Next Steps

So you go through the regular checks mentioned above  , and lo and behold your sender score is as reputable as the Nigerian prince asking for your bank account to transfer money .

What do you do ? stayed tuned for a recovery plan that can get you up in running again within 30 days

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