The 10 Commandments Of Email Delivery: Make It Into The Inbox

The 10 Commandments of Email Delivery: Make It into the Inbox

33% of email addresses change on a yearly basis. (Return Path)

The average number of email accounts per user is currently 1.75 and is expected to grow to 1.86 by 2022.

43% of Gmail users read email without turning images on.

In the world of email marketing to consumers, Internet Service Providers (ISPs) have complete control. They decide which messages get through to a user’s email box and which don’t – meaning that, sometimes, getting messages delivered to treasured members of your subscriber base seems absurdly hard. Despite the difficulties many marketers face with email, the benefits far outweigh the stumbling blocks. ROI from email marketing is said to be roughly $40 for every $1 spent ( This accounts for almost double the ROI of SEO, Mobile, and Internet Display ads. With such phenomenal numbers, almost no other communications channel can rival this return on investment.

In America, 85% of your email database comes from Gmail, Yahoo, and Outlook, on average (  . Spammers, who target these ISPs with unsolicited junk mail, have caused a strong response from ISPs who want to ensure security and privacy for their users. Getting in the inbox even when a recipient has opted in is not guaranteed.


In 2019, Spam messages made up for 55% of all email traffic. Even as responsible senders, your emails may be blocked or undelivered if careful attention is not given to your database, content, and sending practices.

One of the best ways to differentiate your sending from a spammer is to avoid sending to spam traps. Spam traps are either recycled addresses that have been de-activated by the email service provider or created by the service provider with the sole purpose of luring spammers. Due to the prevalence of spam traps, One out of every five emails you send may not ever reach your subscriber’s inbox. ( Spam complaints were the second most common reason for inbox placement issues (21%). Every time a subscriber reports an email as spam, a complaint is recorded by the mailbox provider spam filters. If complaints exceed a certain percentage, all future campaigns bypass the inbox and are sent directly to spam. ( In conclusion, keeping your lists clean by sending to only engaged subscribers will keep spam traps out of your database and help your delivery improve.

Nevertheless, blind faith is not necessary for effective emailing. When followed, a few best practices will help increase your delivery rates. Call them the Ten Delivery Commandments of email marketing.

  1. Consistent Sending Volume
  2. Validate your domain: All of the sending domains you use, including your corporate domain, should have visible WHOIS information and be registered on Hidden domain protection services are often recognized by spam blockers as junk, and mail sent will not be delivered. It’s also highly recommended to have a consistent sending domain and a static “from” address according to the type of email you are sending. In a basic sense, validating your domain shows that your emails are authentically coming from your business.
  3. Acquiring Email Addresses: Email addresses to which you will be sending should be obtained in a transparent manner. Using underhanded tactics like offering a free download and then opting in users to unrelated lists is unacceptable. Be completely clear to the subscriber regarding his/her subscription. Additionally, addresses should not be obtained through third-party affiliates, programs, or vendors.
  4. Always Use Confirmed or Double Opt-In: It is extremely important to obtain explicit permission to send email to your subscribers. Use a double-opt in process to make sure you close the loop when receiving permission to send to subscribers. Employ a “welcome message” upon sign-up to verify the list and content to which a user has subscribed. Remind subscribers to add you to their address books to ensure they receive your content.
  5. Assign Expectations for Content and Frequency: When a subscriber agrees to receive email communication from you, it is important that you are explicit about the content they can expect to receive.
  6. Best Practices for Email Creation: There should be no large images, large attachments (all attachments are discouraged), or messages that consist solely of an image. Do multi -part messages and include a physical business address. Make sure your HTML message structure uses technical best practices and is responsive
  7. Integrity of Content: Email content sent from you should be relevant to your business and related to content on your website. You should not send email communications for third parties. Also, make sure subject lines are relevant to the content contained in the body of the email.
  8. Current Subscriber Activity: it is important to make sure your subscribers are receiving content they find useful and, if not, to provide them quick ways to remove themselves from future mailings or stop engaging with your emails. Subscribers must remain actively interested in your content to keep your database fresh and engaged. Tracking must be implemented to identify subscribers who are no longer engaged, which can be done by unsubscribing those who have not clicked or opened a campaign in more than 12 months. Luckily, engagement filters are in place that can solve this step for you. It is also a good idea to re-opt-in subscribers who have not opened or clicked a message in more than six months. This is called a re-confirmation campaign, and it can help gain back subscribers that have been lost to engagement.
  9. Sender Reputation: Following the preceding commandments creates the building blocks of your sender reputation. Correctly following each guideline serves to boost your reputation as a responsible mailer. This process is a lot like building credit and takes time and responsible transactions to develop trust from ISPs.
  10. Building a Healthy Relationship: Email helps you build a relationship with your customers. This involves two parties agreeing to certain rules and guidelines to continue a relationship in good standing. Should either party become unhappy with the relationship, it is the responsibility of the other party to end communication. Unsubscribe links should be highly visible in all email messaging. Not only is it courteous, it’s the law.

Real-Life Success Stories from Our Delivery Team:

Casino News Put Out with the Trash

  • Problem: A casino’s weekly newsletter keeps landing in the junk folder instead of the Inbox.
  • Possible Causes: The client had limited knowledge regarding email best practices. Marketers had built a good list but were sending from an AOL address rather than a corporate domain.
  • Solution: Client changed the sending domain to a domain branded to the organization and used it in the subscriber email. Additionally, email authentication methods such as SPF, SenderID and DomainKeys were put in place to validate this new sending domain. This helped to get the subscriber emails from the bulk folder to the Inbox.

Church’s Eblast Roadblock

  • Problem: A large church is experiencing poor email delivery rates and is at times completely blocked by ISPs.
  • Possible Cause: Unclear subscription process that didn’t communicate effectively to recipients that they would be subscribed to an email newsletter.
  • Solution: The email subscription process was changed to be clearer in subscription expectations. Additionally, whitelists and feedback loops were put in place. The result was that the client’s email was not blocked and ended up in the Inbox.

Is Spam on Your VIP List?

  • Problem: Over the course of several years, a trendy nightclub built a robust list of subscribers, but is now experiencing low delivery and open rates.
  • Possible Causes:
    1. Disinterested subscribers choose not to open the message and some even mark the message as SPAM, resulting in a negative effect on sender reputation.
    2. The list contains old email addresses that are no longer valid. ISPs recognize the bad address and turn it into a spam trap. If a spam trap address receives mail, ISPs identify the sender and there is a negative effect on sending reputation.
  • Solution: Unmaintained lists are sloppy and don’t efficiently engage clients. Segment or divide the list into recipients who opened and/or clicked, and those who have not. Remove those who have not interacted with your campaign and launch a sender re- engagement campaign to give them a chance to opt back in before they are removed with are-engagement campaign. These changes help to improve open rates two and three times from what they previously were.