Marketing & Communications

Is Your E-mail Getting Through? 10 Keys to Email Deliverability

By • July 5, 2010

When you send your members a newsletter, electronic magazine, or any other kind of e-mail communication, you probably expect that most of the people on your email list are reading that email. Unfortunately, statistics show that far fewer people than you think actually receive the email, and even a smaller number actually read it. Is your content that un-compelling? Are your members not interested? No. The biggest culprits are “spam” filters, meant to capture unwanted email, but which now are also capturing many legitimate communications, including yours.

The main problem with undelivered emails is that both sides—sender and recipient—don’t really know what has happened. Was the email delivered? Did it make it through the network spam filters? Did it make it through the e-mail application’s filters? Did their email application not send a response back acknowledging receipt? Most recipients will never know that an email flagged as spam was sent to them—they just don’t receive the email. And most senders will never know that an email flagged as spam wasn’t delivered—they just don’t get a response.


  • You needn’t be a technology guru to understand and improve your email formatting and delivery success.
  • Everyone involved in sending email on behalf of your organization should have at least a cursory understanding of the 10 email delivery best practices below.
  • Consistency, accuracy, relevancy and trust are among the keys for successful email delivery success. 
  •  At too many organizations, neither the sender nor the recipient is aware that an email has gone undelivered, and that’s a wasted opportunity for building member-to-association bonds.

There are some things you can control and many things you can’t. Understanding how these systems work will help you receive the best results possible.

E-mail Delivery Process

When an email is sent to a valid e-mail address, it passes through the Internet to the recipient’s email server. Assuming that it is a valid e-mail address and that the email server is operational, you will most likely receive a successful delivery attempt. About 98 percent of all of the emails that Naylor sends out for its clients get successfully delivered. It is very important to note though that this does NOT mean that the person actually read or even saw the email. It just means that it did not bounce back immediately.

After reaching the email server, the e-mail must pass through any spam or junk mail filters on the intended recipient’s network. To determine whether a given email is spam or not, most spam filters consider a number of different attributes, such as content, length, percentage of text, use of images, number of recipients, headers and more. Usually they calculate a so-called “spam score” for every email that passes the server. If the mail’s score exceeds a certain threshold, then the mail is blocked and lands in the recipient’s spam folder. If that happens, your email will not be seen unless the recipient remembers to check his or her spam folder regularly.

If your eNewsletter passes the gauntlet of the email server’s spam filter, it is then delivered to the recipient’s email reader. Microsoft Outlook is the most popular of these readers, but there are hundreds of different e-mail readers. Each one also has its own, customizable junk mail settings. Depending on how these are set up, your email could then be caught in that filter, as well. If it is, your email will not be seen.

It’s also important to note that most analytics programs that measure email open rates do so by relying on a small file that’s embedded in the email. When the email is opened by the end user, a notice is sent back to the sender’s mail server. However, some e-mail readers do not allow this return response, which may cause an artificially low (reported) open rate.

10 Keys to Improving Delivery and Open-Rate Success

So, what does all this mean to association marketers and publishers? It means, on average, that only 20 percent to 25 percent of members to whom you send an email will actually read it. The other 70-plus percent either won’t receive it (more likely) or weren’t interested (less likely). Unfortunately, it is impossible to know the exact breakdown of that 70-plus percent.

Because electronic newsletters are an important part of association marketing and communication strategies, the more you can improve your delivery success rate, the better your potential response rates. The principles and rules listed below might help you to increase the delivery rate of your newsletters.

  1. Send newsletters regularly.
    Let your subscribers know when your emails are coming. If you offer a subscription to your newsletter from your website, then tell each and every subscriber exactly when to expect your newsletter.
  2. Tuesday / Wednesday 2-3 p.m. = Increased Response.
    Your subscribers will come to expect your email to arrive in their inbox on the same day at the same time every week, meaning that they want to read your content and are generally more receptive to any special offers or promotions you may include. This means that they are less likely to misunderstand your newsletter and report it as spam.
  3. Slow down your newsletter delivery.
    Instead of using tools that boost your newsletter through mail servers to achieve instant delivery, consider using “slow” delivery tools. Avoid sending mails to multiple (dozens or even hundreds) recipients using CC:-attribute. Use professional newsletter software or professional email-delivery services. When ISPs detect a flood of e-mail, it looks like the work of a virus or a spammer.
  4. Use a tag line at the beginning of the subject line.
    Mark your newsletters as such. Make it easier for your readers to recognize your newsletter. e.g. ‘[SM Newsletter] Nr. 297, 16.10.2007 — Usability Glossary — Splash Pages — Big Typography.’ Remain consistent. Otherwise your readers might consider your e-mails as spam and report it.
  5. Always insert the current date in the content.
    Including the correct date indicating when the newsletter was actually sent is more important than you may probably think. If the date isn’t mentioned or is provided incorrectly, the newsletter is given spam score points and will further irritate recipients if they ever get around to reading it.
  6. HTML is OK, but only if MIME-Multipart is used.
    When sending newsletters in the popular HTML graphical format, make sure you also create and attach a plain-text version of it. Messages sent in Multi-part Internet Mail Extension (MIME) format are automatically sent in such a way that still enables subscribers without active HTML-viewer to get a decently formatted email. It is important that both plain-text and the HTML version have the same or very similar content. The percentage of text should be higher than the percentage of HTML or images. Keep your message size between 20 and 40 kilobytes (Kb).
  7. Use Cascading Style Sheets (CSS) sparingly.
    In most cases it is better to use inline CSS styling in HTML instead of referring to CSS file in HTML. However, referring to external CSS files is better than sending them with your newsletter.
  8. Avoid graphics and complex HTML-elements.
    Spam filters consider a number of issues related to HTML. For instance, if the newsletter has too many closed tags, too many graphic (images) or structural (tables) elements it gets just as many spam score points. Besides, many readers use software (e.g. Outlook) that automatically blocks images; if users don’t understand what the mail is about they’ll report is as spam. Complex HTML (particularly if more than 50 percent of HTML code is HTML tags) is generously awarded with many spam score points—so keep it simple. Colorful backgrounds, tables, Java scripts and web forms shouldn’t be in newsletters.
  9. Motivate your users to add you to their whitelists.
    To ensure the bulletproof email delivery, ask your readers to add you to their “whitelists.” A whitelist is a personal list of “trusted” email senders and is managed in the recipient’s e-mail reader. What’s a good way to encourage your members to add you to their whitelists? Just ask them to do so in your emails.
  10. Verify your subscribers with signup confirmation.
    Only send email to people for whom you have a legitimate business relationship. Sending your email to a list of recipients who have opted-in to receive that communication is best, but sending e-mail to your paid membership base is fine, as active communication is part of your promise to your member. Never buy third-party email lists and send them unsolicited mail.

Verifying also keeps invalid e-mail addresses off of your list, which reduces the volume and percentage of undeliverable messages that you send. Since undeliverable rates also factor into filtering rules, keeping invalid email addresses from being subscribed to your list will help you to avoid content filtering.

By keeping your content as relevant as possible to your distribution list, by constantly cleansing your list regularly and by following the 10 delivery tactics outlined above, you’ll soon find you’re receiving fewer undelivered emails, more accolades from your readers and much better numbers in your analytics reports. That’s a win-win from both sides of the member communication equation.

Marcus Underwood is vice president and general manager of NaylorNet, the online media solutions division of Naylor, LLC.