Email deliverability is like a mythical sphinx wrapped in a 3,000-piece jigsaw puzzle. An incredible number of factors go into whether your email was delivered, how fast it was delivered and where it landed (primary, social, promotions tab, or the dreaded spam folder).
Also, every ISP, like Gmail, Yahoo or Hotmail, behaves differently when it comes to accepting email, and they are very tight-lipped about their algorithms.
Finally, once you attain a good sender reputation by properly warming up your IP address and cleaning out your hard bounces and spam traps, you must work hard to maintain it by continuing to send highly-engaging emails at regular intervals to clean lists.
Here are five tips for the email deliverability-obsessed to help you better understand the science behind email delivery and use it to improve your sender reputation, deliverability and delivery speed.
1. Work With A Good ESP That Removes Hard Bounces
Hard bounces are emails that have been returned to the sender because they are permanently undeliverable. This could be because the email is invalid (outdated, no longer in use, misspelled, made up, etc.) or because the recipient’s email server has blocked your messages.
Hard bounces are often called “spam traps” because if you continue to send emails to hard bounced addresses, ISPs will consider you a spammer and your deliverability will suffer.
One way to avoid hard bounces is to never buy lists, as they may contain false email addresses. Also, if you’re working with a stale list, it may be helpful to use a list cleaning service such as BriteVerify or DataValidation which can verify the validity of your subscribers. (Note I’m not affiliated with either company).
But most importantly, to maintain a good clean list, you should work with a good email service provider (ESP) that automatically removes hard bounced email addresses from your subscriber base. This way, you can make sure you do not send messages to these “ghost subscribers” ever again.
2. Sanitize Lists By Removing Users Who Haven’t Engaged
Marketers shudder when they’re told to shrink their subscriber lists. After all, a lot of work goes into growing an email list! But if the Pareto principle holds true that 80% of the effects or profits come from 20% of your customers, then it’s likely your list could shed some inactive users.
A smaller list of highly-engaged users is better, will generate a higher ROI and receive higher email deliverability than a giant list of dormant subscribers.
A good practice is to perform regular list sanitization by removing subscribers who haven’t clicked, opened or made a purchase from your emails in the past 90 days from regular blasts. This lets ISPs know that you’re sending emails to people who want them. Failure to comply could delay email sends or have them not be sent at all.
You don’t have to completely delete those emails from your subscriber base. You can always save them for a quarterly re-engagement campaign. Or you can divide your subscribers into various cohorts depending on their engagement level and create different email marketing campaigns for each subscriber segment.
3. Personalize The “To Name” Of The Recipient
Most companies collect the first and last name of the recipient and use that data to personalize the subject line, preheader or message content. An advanced deliverability trick would be to also use the full name as the “to name,” rather than just the email address, which notifies ISPs that you’re sending emails to people you know that have given you permission to reach them.
Here’s an example of a sender that’s only using the email address for the “to name.”
And here’s an example of a sender that is also customizing the “to name” with the subscriber’s first and last name:
4. Use At Least One IP Address For Each Email Type
For any company sending email, the reality is some of your messages will get marked as spam.
Sometimes, subscribers get overwhelmed by messages or get too lazy to scroll down to click the unsubscribe link. And if enough people mark your emails as spam, this alerts ISPs that you may be a spammer, even if you’re a legitimate business that acquired subscribers through permission marketing and not by purchasing lists.
Generally, marketing emails tend to get marked as spam more often than transactional emails, since they arrive often and don’t contain critical information like order or shipping confirmations. Therefore, if you’re using an email service provider that provides dedicated IPs, you should have at least one IP address each for your transactional, promotional and marketing automation emails.
This ensures that even if people mark your promotional marketing emails as spam, that will not interfere with the deliverability rates for your business-critical transactional emails or your high-value, shopping-cart-abandonment automation emails.
5. For Large Sends, Try IP Bonding
Again, if you are working with an email service provider that provides multiple dedicated IPs, you may want to try IP bonding for large sends, since ISPs limit the number of connections each IP can make.
Therefore, IP bonding, which is the practice of using multiple IPs for a send, can diversify the reputation of your IPs and speed up a send. Each IP has a different reputation and send speed. Therefore, for sends of 500,000 or more that need to arrive by a certain time, be sure to spread the send out across multiple IPs. This is a great practice for flash sale announcements or other time-sensitive messages.
Email deliverability is tricky and impossible to master, but if you take time to understand how ISPs process emails and follow these advanced strategies, you can enjoy higher deliverability and send speeds.
Opinions expressed in the article are those of the guest author and not necessarily Marketing Land.