Improving Deliverability

The average person checking their email typically does not realize that there is more than meets the eye in their inbox. When an ISP (Gmail, Yahoo, Comcast, etc.) receives an email from a marketer, one of three things happens:

  1. the message is delivered to the inbox
  2. the message is delivered to a spam or junk folder
  3. the message is blocked altogether – a marketer’s worst nightmare

Any message that fails to make it to the inbox is a lost revenue opportunity to businesses, which is why deliverability is a topic so near and dear to marketers. That said, while we often hear people referring to deliverability as a “black hole” that can never be fully understood, in reality there is actually a silver bullet solution to optimizing your delivery: list health. If the health of your subscriber list is good, and you are sending mail that your recipients LOVE, your mail will reach the inbox.

ISPs receive billions of messages a day and are unable to accept and deliver all of them at once. As a result, they rely on advanced algorithms to determine a “reputation” for each stream of incoming mail and 95% of all mail is blocked outright. Your reputation score dictates whether your mail will be delivered to the inbox, to the bulk folder, or either throttled (put into a waiting queue) or completely blocked (mail will not be delivered until someone reaches out to the ISP requesting unblock, and it should be noted that the likelihood of an unblock being granted is again based on your reputation). This begs the important question, what factors play into my reputation? Most importantly, list health!

There are four main considerations at play for the ISPs when determining reputation for a mail stream:

User Engagement

Does the user want to receive this message? The best indication that the mail is wanted/welcomed is when subscribers open and engage with the message. Ten years ago “spam” was associated with a message from a person or brand you clearly had no intention of engaging with (think back to all of the Viagra emails!); you didn’t sign up for messages, and you had no use for them. In that era, it was easy for ISPs to look at message content and quickly determine whether it was spam (and block it if so). Now, however, the ISPs seek to fight inbox clutter, meaning the qualification process for spam has changed significantly. Messages from trusted brand names can be considered spam. To mitigate the risk of that happening, marketers must concentrate on keeping their audiences highly engaged (e.g. pay close attention to open rates). For example, if a user has not opened in a specified period of time, the marketer would ideally start sending to that user less frequently. If the user is still not engaging with the less frequent messages over a prolonged period of time (or any of the re-engagement emails you should definitely be sending them during that period), it may be time to remove them from the list entirely. Keeping unengaged users in your list can negatively affect your sending reputation.

User Complaints

At the opposite end of the spectrum from engagement are user complaints, which explicitly indicated to the ISPs that the mail is not wanted. User complaints occur when a user hits the “spam” or “junk” button. As a general rule of thumb, you should always target a complaint rate below 0.2%.

User Invalids

Invalid email addresses are those that have hard bounced and are a group of users the ISPs monitor closely. If you are following best practices and only mailing to users who have explicitly opted in to receive your messages, you typically should not have an issues with high invalid counts. That said, if you see your hard bounce rate float north of 0.8%, you should evaluate the signup sources you are relying on for your list to determine if certain sources are sending you less qualified traffic.

Spam Traps

Spam trap hits are hands-down the number one way to identify list hygiene issues. There are two types of spam traps: recycled traps and pristine traps.

A recycled trap is an email address that was at one point valid but that has since been either abandoned or closed; in other words, the address is presently invalid, meaning the ISP will bounce it back to the ESP. To create a recycled trap, the ISP will make the invalid address live again after about a year of bouncing the address back to the ESP as invalid. The ISP will then use this recycled trap to catch mailers who are sending to addresses that have been marked as invalid for over a year.

A pristine trap is an email address that has been created by either an ISP or blacklist, and it’s placed in a location where it’d be very rare for a person to come across it (e.g. in source code); these addresses are mostly picked up by bots and scrapers. Because these addresses are not readily accessible to people, typically the only way they’ll appear on a list is if the list was bought, etc. (which violates best practices). To proactively avoid pristine traps, be sure to 1) only mail to users who have explicitly opted in to receive your messages and 2) proactively remove registered users who have not opened in over a year (a spam trap will never open a message).

Onboarding Best Practices

In the onboarding process, please upload a list of previously hardbounced and opted out users to Sailthru. This will ensure better deliverability by making sure these users are never erroneously sent to. Your Project Manager and Customer Success Manager will help to guide you in this process.

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