Understanding the Importance of Email List Quality

According to our 2016 Email List Strategy report, 71% of marketing professionals asked about their email list strategy goals said that increasing list quality is a priority. In my opinion, this should be much higher. Maintaining a clean subscriber list is so important to the success of an email campaign, as the quality of your list can determine whether your email lands in the inbox or spam folder, or gets outright blocked by the mailbox provider.

But what does maintaining a high quality list mean? It means that your subscriber list should be free of any spam traps, unengaged subscribers, and unknown users. Need any of these terms defined? Check out our Email Deliverability Glossary.

Let’s start with spam traps, of which there are two kinds and both are indicative of poor list quality. A pristine or honey pot trap shows mailbox providers that a marketer’s list acquisition practices are, for lack of a better word, sketchy. These types of traps typically enter a subscriber list via website scraping or list purchases, or through a bad data partner. Recycled spam traps, on the other hand, are a sign to mailbox providers that the marketer is not practicing regular list cleaning based on engagement or properly removing bounces. Both types of traps can have a significant impact on your email deliverability and cause your emails to land in the spam folder, or be blocked altogether.

Now, let’s talk about unknown users. Mailbox providers typically like to see unknown user rates under 10 percent (and even lower is better). This means that less than 10 percent of your list should be made up of invalid email addresses. And yet, according to BriteVerify usage statistics, it is estimated that 7-15 percent of online forms and point-of-sale entries contain invalid, undeliverable emails, mostly due to common typos. If you are not validating email addresses at point of capture, or on some sort of regular basis, then it’s very likely that you have more unknown users on your list than you should – and this could be hurting your email deliverability and overall revenue impact from email. Sending to unknown users will lead to an increase in bounce rates, which is another sign to mailbox providers of poor list quality. This, in turn, can lead to a poor sender reputation and cause more mail to land in the spam folder.

Finally, a marketer should also consider the number of unengaged subscribers on their email list. Mailbox providers, especially the major global ones like Gmail and Yahoo, are taking subscriber engagement into account when making inbox or junk folder placement decisions. They want to see that marketers are sending to subscribers who are active in their mailboxes, and that unengaged subscribers are being routinely cleaned from the email list. A re-engagement campaign is a great way to determine if unengaged subscribers want to remain on your list or not, or you can optimize your sending frequency to help re-engage subscribers. Either way, unengaged subscribers should be removed from your regular email list as, just like spam traps and unknown users, these too can hurt your sender reputation and overall deliverability.

As we look into the future and approach the year 2020, Return Path has hypothesized that we will continue to see mailbox providers get even stricter with their filtering policies, meaning that marketers will need to get even more diligent about maintaining a high quality subscriber list. As the golden rule of email marketing states, it’s important to send timely, relevant emails to people who want to receive them. Sending to people that want to receive your emails means that you are working with an opted in list of valid, engaged subscribers, and are regularly cleaning your list to ensure it stays this way. Without this diligence, you risk hurting your sender reputation, deliverability to the inbox, and ultimately your revenue potential from email.

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