Email list building and hygiene

Key findings on list building and hygiene

How does your email list impact deliverability?

Why would mailbox providers care about the database you use to send email messages? What does your list of contacts have to do with achieving inbox placement? Here’s the answer... The quality of your list and the way your contacts engage with your emails send signals about what kind of sender you are.

Imagine a parent checking out a teenager’s bedroom. If it’s a mess of fast-food wrappers, dirty laundry, and unfinished homework, that parent might assume the teenager is lazy and irresponsible. Maybe that teenager doesn’t deserve certain privileges.

Likewise, to earn the privilege of reaching inboxes, you’ve got to keep your act clean.

When you focus on these things, mailbox providers are much more likely to see you as a reputable sender who deserves inbox placement. The senders who took our survey find that to be true.

Among those who prioritize list hygiene, 47.5% say the biggest benefit is maintaining a good sender reputation with mailbox providers like Gmail, Yahoo Mail, and Outlook. Better engagement metrics (19.4%) and fewer spam complaints (17.8%) also emerged as top benefits, and that’s also correct.

We take a closer look at sender reputation in Chapter 5 of this report. If you’re unfamiliar, this is a unique score mailbox providers give senders based on a variety of factors. The health of your email list contributes to several of those factors.

“We often compare email sender reputation to credit scores. In both cases, one costly mistake can easily damage your credit score or your sender reputation, but they take time to build back up. That’s why you need to take steps to maintain a good reputation with mailbox providers.”

Ashley Rodriguez

Deliverability Engineer II, Sinch Mailgun

Email list building practices

The foundation of a healthy contact list starts with how you collect email addresses and confirm someone’s intent to subscribe. Obtaining proper consent, especially for promotional messages, is critical to any email program.

If you’re emailing people without consent, you are a spammer, and your messages belong in the junk folder. What’s more, without explicit consent, you may be violating important consumer privacy laws and could face significant fines.

Unfortunately, questionable methods are still being used. Nearly 1 out of 10 senders in our survey (9.4%) admit they’ve either purchased email lists or scraped the web for contacts in the last two years.

The good news is that 85.5% of the senders in our survey have not used these practices in the last couple of years while about 5% are unsure. But just wait... there’s more bad news.

When we look at monthly send volumes, it turns out that organizations sending more email are also more likely to add contacts to their lists without obtaining consent. Around 15% of senders with volumes between 100,000 to more than 1 million emails per month admit to these questionable practices.

Sinch Mailgun research also found that B2B senders are almost three times as likely to use questionable list building methods compared to B2C (12.3% vs 4.3%). Purchasing lists and scraping are tactics often used for cold emailing B2B prospects from the sales team. It’s one thing to cold email people individually, but once it’s automated for scale, you’re entering the world of spammers.

Building a qualified email list organically takes time and effort. You’ve got to overcome the temptation to simply buy a list of contacts that fits your target audience or there could be consequences.

A better way to build your email list

There are many ways to collect contacts without spamming people and violating privacy laws:

• Place signup forms on key pages of your website.

• Start an industry newsletter to attract relevant subscribers.

• Offer valuable content in exchange for contact information.

• Allow people to subscribe to regular deals or product updates.

• Collect emails during online checkout or at the point of purchase.

However, even after someone fills out a form, there’s another step you can take that supports email deliverability. It’s called a double opt-in, and it involves sending an initial email to new contacts asking them to confirm their intent to subscribe.

This process does mean list growth may be a bit slower. However, it also ensures you’re only adding new contacts who really want to be on your list. These contacts are more likely to engage with what you're sending.

“I would recommend that every sender use a double opt-in all the time. Not only does it ensure you only acquire subscribers who are more likely to engage, but it also helps prevents bots from abusing signup forms, which is a significant email security risk.”

Nick Schafer

Sr. Manager of Deliverability & Compliance, Sinch Mailgun

Sinch Mailgun’s research shows nearly 40% of senders are using the double opt-in method while more than 47% are not and about 13% are unsure.

A compromise to the strict double opt-in method is something called confirmed opt-in lite (COIL). This is when you only send certain emails to new subscribers, such as a welcome series or a monthly newsletter, until they engage. Once they do, you can add them to your main email list knowing they likely have a legitimate interest in what you offer.

Email list hygiene practices

You can get away with skipping a shower or two. Bathe once a week and maybe no one will notice. But try not showering for a month and see how people react when you walk into the room. When you have poor email list hygiene, it’s mailbox providers who think you stink.

Here’s what Sinch Mailgun’s research reveals about how often senders conduct email list hygiene:

• 27% Monthly or more

• 16% Quarterly

• 18% Once or twice per year

• 27% Rarely

• 12% Never

How often you need to conduct list hygiene depends on your list and the rate of growth. But if you’re among the nearly 40% who rarely or never conduct list hygiene, you’re putting your email communication efforts at risk of deliverability problems.

One of the most effective ways to manage your email list is to implement a sunset policy. This involves setting specific thresholds or benchmarks for segmenting unengaged subscribers. For example, if someone hasn’t opened an email from you in three months, that contact is “sunsetted” or moved off the main list.

Our research found sunset policies are uncommon among typical email senders. Just under 24% of all senders use a sunset policy. Nearly 59% say they do not and about 17% are unsure. These findings are almost unchanged from what we found in our 2023 survey.

Sunset policy implementation increases significantly based on email send volumes:

These findings suggest tactics that help senders proactively manage list hygiene become more important as their contact databases grow.

How email validation tools can help

Another way to proactively manage list hygiene is to validate emails at signup before you add them to your database. People make typos when filling out forms, like entering gnail.com instead of gmail.com. But you can help them correct those mistakes, so you don’t lose out on new contacts.

The process of email validation does more than catch typos. It also verifies that an address can accept mail, it checks syntax for correct formatting, identifies disposable emails, and catches high risk email addresses.

Senders may verify emails at signup, and they can conduct bulk email validation on an entire database as part of regularly scheduled list hygiene. Both these methods are useful for maintaining a quality email list. One keeps bad contact data from getting on your list, the other helps you clean up the data that’s already there.

We asked senders to identify the ways they validate emails. 30% conduct email validation at signup and almost 13% use bulk validation (only 3% do both). 38% are manually removing hard bounces and 24% say their ESP does this automatically. 28% say they aren’t using anything to validate emails.

Email validation also helps senders reduce bounce rates and maintain good engagement metrics. If you have invalid or outdated contacts in your database, they’re not engaging with what you send, and that will drag your metrics down. List hygiene leads to a clear picture of email program performance.