Email Deliverability and Reputation Management ©APD 2015


APD's Guide to Email Deliverability

Click here to download and print a pdf version of APD’s Guide to Email Deliverability

You understand the legal and best practice rules. You ask permission to send emails and get all the right details including a valid email address - so why might it still be difficult to get the email to the people that want it?

Why can’t every email get delivered?  In an ideal world an email is sent from your organisation straight to the inbox of the recipient. Inbox placement is the goal of Email Deliverability, but there are a lot of reasons why this does not always happen.

How is it measured?

Email deliverability is complex, so it is measured and reported in a number of ways. It is part art and part science. We look at information which is bounced back from the recipient mail severs to deduce whether an email is delivered or not. We review open rates and click through rates and add them together to get ‘activity’ rates. You can also use a method you have probably heard of called inbox placement testing. Inbox placement testing is a process where email address ‘seeds’ are added to a list. Usually 12 email addresses for the most common ISPs.

During the send (email broadcast) these seeds receive emails once to each address at different times throughout the time that messages are sent. This should represent testing at different times during the course of the campaign.

This is the method which everyone uses for inbox testing, including APD and organisations like Return Path. Using this method we can tell if there are any issues during the send and at what point. This is purely extrapolation. Return Path tests over 140 domains, which include all of the popular American ISPs, but only 3 New Zealand and 3 Australian ISPs, which is why we do it to ensure a wider net is cast.

There is no tool which will tell a sender exactly how many messages are placed into the recipients’ inboxes.

What role do the ISPs play?

ISPs control the email accounts for your recipients. That is Yahoo (which is also behind Xtra in NZ), Gmail, Hotmail and hundreds of others. APD estimates that the top 3 ISPs account for over 75% of all inboxes. That is a little under 30% for Yahoo/Xtra, a little over 30% for Hotmail (now also Outlook.com) and over 16% at Gmail.

The ISPs are responsible for serving their clients (the people on your database), rather than serving your business. When dealing with ISPs, it's all about trust. Their core role is to deliver the emails that their users want, without letting too many unwanted messages through to fill up their users’ inboxes.

ISPs use filtering and reputation monitoring to decide what to do with the email you send to their ‘client’.

The ISPs monitor your reputation as a sender and use it to determine whether your emails are junked, or sent to the inbox. Spam complaints harm your reputation, and over time, harm deliverability. The opposite is also true: consistently low complaint rates can improve your reputation over time. The ISPs need to trust that a sender will not generate too many complaints, or abuse their system or resources.

Your Email messages jump through many hoops to get to an inbox and it is estimated that 3-5% of all email never makes it due to filtering mechanisms installed by ISPs.

The tools that ISPs use to reduce the risk of unwanted messages getting into the inbox are often global applications designed to filter or block unwanted messages.

Understanding Content Filters

One of the ‘layers’ of control is a Content Filter which looks at the ‘Spamminess’ of a message. 

Content filters have evolved into many thousands of complex rules in order to more accurately identify Spam Messages. Circumventing content rules is not an easy process, unless there is some glaringly obvious content, which you can change and re-test to try and get a ‘pass’. For example, we had a campaign triggering filters and we eventually deduced through a series of tests that a celebrity perfume brand was the issue due to the celebrity in question having been used in x-rated spam content.

For more complex filters, it is often necessary to get the filter creators to review the message and write a rule or modify the existing rule to exclude the message.

This is not an easy process and as with most changes to filtering or blocking we need to establish a level of trust that the messages are wanted and that the sender adheres to the highest standards of permission-based senders.

Reputation-based email rules are critical

Reputation is a broad term that means how you are perceived by the email infrastructure and is based on the aggregation of complaints, sender volume and frequency. It also measures other things such as reader engagement – if you send emails that are not read to Gmail for example, Gmail ‘sees’ the recipient isn’t very interested in you and makes, what is effectively, a small black mark against your name. 

Unfortunately, these rules do not take into account permission. The ISP or Filtering technology provider is simply attempting to determine how ‘wanted’ the message is, based on their experience of complaints from people who receive the message, the behaviour of the sender, or, with some more advanced ISPs, the level of engagement as seen by messages read or deleted.

ISPs favour Reputation over most other methods to identify unwanted emails.

Reputation is earned with actual experience and it’s very low risk for the ISP because it’s clearly factual. If you delete every email a brand sends you, they will assume you don’t want the emails.

Reputation is not easily changed since it’s built slowly over time. It’s therefore critical to get things right the first time and not engage in risky behaviour that might result in increased complaints.

How do these filters and rules affect the messages we send?

There are only a few possible outcomes when you send an email message:

Block - Hard Bounce
Bulk - Goes into the Spam Folder - Quarantined
Deferred – A deferred email is listed as a ‘soft bounce’. We are told to wait and try to send again later. SmartMail Pro will retry every 15 minutes and if the email is not accepted, it will remain reported as a soft bounce.
Inbox placement - Success!

• The message passes all content rules, reputation rules and the sender is not found on any blacklists – the email is placed into the inbox.
• The message fails a content filter and as a result is either Blocked (Hard Bounced) or placed into the Spam Folder.
• The message comes from an IP address that has a low reputation. The message is therefore classified as too risky to put into the Inbox and is either Blocked (Hard Bounced) or placed in the Spam Folder.
• The sending server does not ‘play nice’ or measure up to the ISP's email server requirements and results in all messages being delayed or Blocked. This can be the result of sending messages faster than the receiving email server wants to receive them, or too many bounces (A common tactic of Telstra Clear, Paradise)
• Too many immediate complaints where the recipient hits ‘mark as spam’ or ‘send to junk folder’, so the ISP will respond immediately with a Block or Bulk.

What CAN you do to make sure your email is delivered?

Large and Small, Big and Small, B2B and B2C Organisations can all do the right thing.

Wherever possible send email that is anticipated, personal, and relevant to your recipient. Adhere to best practice and you will continually improve your sender reputation and build trust with ISPs. 

In addition you should have provision for time and resource to include the following:

Proactively remove bad data – list hygiene doesn’t ever finish. Let people update their own details from every email you send. Monitor soft bounces. Clear out true hard bounces. Make unsubscribing as easy as possible.
Work at engaging your inactive subscribers - the more engaged your subscribers are, the more inboxes you get into. 
Set clear expectations and confirm the opt-in – make sure your opt-in is as good as possible. Use validation and send a confirmation email to ensure the email address is valid. Note: a Confirmation or Welcome Email is not the same as double opt-in. You are simply sending an email to welcome them. Set the expectation that your email program will always deliver on your opt-in promise and make sure the address is valid.
Track overall results - run A/B and multivariate tests on subject lines, offers and other aspects to improve engagement.


How does APD make it easier for you to earn trust with ISPs?

• Dedicated IP addresses. This means that an ISP knows that an IP address will only send email from the registered sender, making it much easier for them to manage an issue if it arises.
• Authentication. We sign our messages with the mainstream methods of global authentication, so the ISP knows who is sending them. In layman’s terms, this is like having a ‘Sender’ written on the back of your envelope.
• Dedicated sub-domains. This means that it’s easy for the ISP to match the Domain with the Sending IP address.
• Feedback loops. Signing up to receive complaints directly from ISPs, in itself helps to earn reputation and it tells the ISP who is using the IP address and that we respect permission.

Larger Organisations with a strong B2C focus may also benefit from being whitelisted


White listing is the practice of requesting that the ISP adds an IP address to a Trusted Senders list on their mail server(white list). All email servers have the ability to Whitelist.

This is a significant risk for most ISPs, as whitelisting bypasses the filtering technologies. Larger ISPs have dedicated postmaster teams and have developed processes to manage the risk. They allow us to apply to be evaluated for the privilege and, if we get the boxes all ticked, your emails will be delivered without the higher levels of filters and into the inbox. Due to the resources required to manage whitelisting, smaller ISPs prefer to rely on the filters to do the job.

In Summary

Improving Inbox placement is about establishing trust as much as it is about sending inoffensive emails. Doing all the right things is a great start, but just like any relationship it is consistent and responsible behaviour that counts. Planning for a great email program, proactive management of complaints and working with ISPs directly on any issues of falsely identified messages, builds long term trust.

APD can help you improve your email performance, including your email deliverability. Contact your Account Manager on +64 9 360 6463 for more information.

Getting your email marketing
to work for you is just one
step away.


Get the
inside word
from the experts
of digital marketing.


Subscribe
Our monthly digest of email marketing
news and insights that we think you’ll find interesting.

Name:     
EMail:     
Take the 4 Minute
Online Tour


Asia Pacific Digital