Email Deliverability Knowledge

The world of email deliverability is a tricky subject, with many nuances surrounding the decisions behind emails being blocked, landing in the spam folder, etc. Understanding why Inbox Providers (Gmail, Yahoo, etc.) filter emails to the spam folder, or block emails, is crucial.

Why do Inbox Providers filter and block emails? 

Over 90% of the mail Inbox Providers see on a daily basis is outright spam. This is mail that no one signed up for. It could be anything from email scams to phishing attempts to simply unwanted mail. The main goal of Inbox Providers is to keep their customers’ inboxes clean of spam. In order to meet this goal, Inbox Providers are using machine algorithms to identify wanted mail vs not wanted mail. They are really weighing positive signals vs negative signals from each sender. 

What are Positive Signals?

If a subscriber opens your email, clicks on a link in your emails, or they mark the email as important/star the email - these are all positive signals that show that you are sending wanted mail.

What are Negative Signals?

If a low percentage of subscribers are opening your emails, that is the first sign your mail is not wanted mail. Inbox Providers are also keeping a close eye on two very important metrics: bounce rate and spam rate. The bounce rate is the percentage of emails that were sent to email addresses that don’t exist. The spam rate is the percentage of subscribers that marked your email as spam or simply moved your email to the junk folder. The spam rate is the single most important metric when it comes to emails landing in the inbox vs the spam folder. 

Drilling down on Spam Rates

As mentioned above, the spam rate is crucial to monitor in order to make sure you are not seen as a “spammy” sender. There are three main reasons why a recipient marks your emails as spam:

1. They never expected to receive an email from your brand
2. They are receiving too many emails from your brand
3. They tried to unsubscribe and you continued emailing them

If you are seeing complaint rates above 0.08% (1 complaint out of every 1,000 emails sent), you need to identify if the issue lies within one of those three reasons and alter your email program to reduce complaint levels. 

Keeping Bounces to a Minimum

A hard bounce occurs when you send an email to a subscriber and the Inbox Provider provides a ‘bounce’ response because that email address is not valid. If your bounce rates are over 2%, Inbox Providers question your email list. Did you purchase an email list? Are you sending to old, inactive subscribers? These are all red flags to Inbox Providers. Running your email list through a list validation service can help reduce bounce rates. 

Developing a Sunset Policy

Every successful email program has a sunset policy in place. This is a policy for how you handle old, inactive subscribers. If you continue to send to inactive subscribers, Inbox Providers view that as spammy behavior and you might see spam placement for your emails as a result. Of course there are various types of mail programs and each has their own nuances, but best practice is to not send emails to subscribers that have not opened and/ or clicked on your emails after 4-6 months. One major risk for sending to old, inactive subscribers is the risk of hitting spam traps. 

Avoiding Spam Traps

A spam trap, in its simple form, is an email address that should not be receiving mail. There are three different types of spam traps, and each type tells a different story as far as what area of your email program needs to be altered. 

Pristine: These are email traps that were created for the sole purpose of being a spam   trap. You will typically see pristine trap hits when you purchase email lists. 

Typo: Just as it sounds, gmial.com, yahooo.com, all of these common typo domains could actually be spam traps. 

Recycled: The most common type of spam trap. These are old, inactive email addresses that were on at one point used by someone. After they stopped logging into their account, it was turned into a spam trap to catch subscribers sending to old, inactive email addresses. 

Staying off Blocklists

A blocklist is a real-time list that identifies domains or IP addresses that have spammy behavior or are known to send spam. The two main ways you can end up on a blocklist is by hitting spam traps or generating spam complaints. Any mail sent from an IP or domain that is currently blocklisted will likely be blocked or delivered to the spam folder. If you do end up on a blocklist, it’s important to follow the steps laid out by the blocklist service to remove your IP or domain. 

Recap

Inbox Providers are simply trying to protect their users’ inboxes from unwanted mail. If you want to stay in good standing with Gmail, Yahoo, etc, follow some simple steps…

1. Send only to recipients that opted in to receive your emails.
2. Stop sending to subscribers that are not engaging with your emails.
3. Make it easy for your subscribers to unsubscribe. 
4. Run your lists through email validation if your bounce rates are too high.
5. If you are generating spam complaints - find the root cause and fix the issue.