Blacklists 101 - stairs leading to do not enter sign


It’s that time of year again. Marketers are planning for the holidays; looking at how they can drive more revenue through email. It’s very common to see people mailing a little deeper into their files than they normally do, in an effort to reengage the people who haven’t purchased or interacted in a while. It’s easy to overstep the bounds of email best practices, and get yourself into trouble. That trouble commonly comes in the form of a blacklisting.

What is a blacklist?

A blacklist is essentially a list of bad actors. Those bad actors are generally spammers, but any legitimate mailer who doesn’t adhere to best practices can be impacted. Blacklists can be domain-based, URL-based, or more commonly, IP-based. They are generally run by independent operators, or organizations whose customers are ISPs, hosting companies, or corporate mail managers.

How do you get listed?

Blacklist operators most commonly use networks of spam traps to catch spammers and marketers behaving badly. (Check out the series I wrote about spam traps earlier this year for more info.) Mailing to spam trap addresses is a signal that you have poor list hygiene practices, since those addresses don’t belong to real users. Depending on the type of trap you mail to (or hit) and the number, you may get flagged as a bad actor and end up on a blacklist. In some cases this is an automated process, in others (generally in more severe cases) it’s manual.

What happens when you get “listed” on a blacklist?

A blacklist is commonly used by mail receivers (ISPs, hosting companies, etc.) to block unwanted mail from bad actors. The amount of mail blocked depends on which blacklist listed you. Some are more impactful than others, based on which mail receivers use them. Spamhaus, for example, is the most widely known blacklist and is used by some of the major mailbox providers. So a Spamhaus listing will have a big impact on your program.

What can you do to resolve a blacklisting?

Each blacklist has it’s own removal process, which can be automated or manual. Either way, it’s important to understand what caused you to get listed in the first place. Did it happen right after you mailed to an old, inactive file? Are you working with a new affiliate? Is a suppression process broken? Once you have identified and resolved the issue that caused the listing, the next step is to reach out to the blacklist operator via their process to request removal.

What should you do to avoid blacklists in the first place?

The best way to avoid the blacklist is to mail to recently engaged users. We recommend those who have opened or clicked in the last 90 days. It’s understandable that marketers want to leverage their email programs to increase sales during the holidays, so a 90-day activity window isn’t always doable. If you do end up reaching deeper into your list, you shouldn’t be including anyone who hasn’t engaged in over a year. Past that time, you run the risk of hitting recycled spam traps (once engaged users, now long-dormant accounts). In addition to a short activity window, double opt-in (or COI) is a great way to avoid mailing repeatedly to spam trap addresses, since they won’t click the confirmation link. We also highly recommend that you use a reCAPtCHA at sign-up to mitigate malicious signups.

Things to keep in mind…

Having a way to monitor your IPs and domains for blacklistings is always a good idea. At Sparkpost, we proactively monitor listings for our Premium and Enterprise customers using the 250ok platform. Also, as I alluded to above, not all blacklists have the same impact on your program. If you see a listing through a monitoring service or in your logs, check your stats in the Sparkpost UI (blocked messages) to gauge the severity of the listing. While you might not see a big impact from some smaller blacklists, they can be a good signal to let you know something is off with your program that might turn into a bigger headache down the road if you don’t address it.

— Clea

Weekly Email Marketing News Digest

This week, we’re looking at the fundamentals of email marketing – why it continues to be relevant and important, as well as why we need to ensure that deliverability is the top priority for marketers.

If customers do not receive your email, it means that they are not going to buy from you – plain and simple. That’s because they’ve not heard about your great new product, or that huge weekend sale, which means they won’t take action. The result? Your email ROI suffers. That’s a big deal since email continues to be the main channel that businesses rely on for ROI.

Billions of Opt-in Email Messages Never Reach Consumers, Return Path Study Finds 

Return Path‘s Inbox Placement Rate (IPR) Benchmarks Report shows that 22% of marketing emails that subscribers had opted-in to did not reach inboxes in the first half of 2013. 18% were blocked or went missing and 4% were delivered to spam or junk folders. The Inbox Placement Rates have declined since 2012 by 4%. The biggest decline was seen in Asia Pacific, which fell by 22% to 64%. One-third of all marketing emails sent there were never delivered.

The Return Path results call to mind the importance of not just deliverability, but working with an email solution and partner that is able to ensure your sender reputation and sender score are in good standing with the ISPs.

Focus on the Fundamentals

Responsive design and behavioral targeting are all well and good, but before embarking on ambitious advanced tactics, it’s critical to get the basics right first.

  • List growth: Ensure that interested subscribers are able to join your list without obstacles and they receive validation, on-boarding and welcome transactional emails in a timely manner.
  • Content: Send your subscriber base regular and strong messaging about your products or services.
  • List hygiene: Are you CAN-SPAM compliant? Are unsubscriptions and bounces being removed in a timely manner?
  • Reactivation: Do you have a reactivation process in place to re-enagage with inactive subscribers.
  • Testing: Is testing a central part of your email campaigns?

If you are not following these email best practices when it comes to these items in the above list, then you should probably get that in order before moving on to advanced features.

More Than One in 10 Emails Are Faulty

A recent study shows that 11% of marketing emails had one or more broken links. In addition, 9% of emails read on mobile phones and tablets had one or more broken links. More than 5% of all emails contained a broken image. Usability and readability issues have negative repercussions on a brand’s reputation so it’s important to ensure that email campaigns are effectively executed and deployed.

Deliverability Myth Discussed

What are some of the deliverability myths you have heard throughout your career? Here are some of the common ones:

  • Myth 1: Deliverability is all about who you know at ISPs.
  • Myth 2: You can’t use certain words in subject lines.
  • Myth 3: Deliverability is a black art that few people understand.
  • Myth 4: Deliverability experts work for the “other team”.

For more information on why these myths have been debunked, check out the original article.

10 Simple but Essential Email Marketing Tips

Want to find out how to reduce your email costs as well as ensure that your email is getting into the inbox? Download our free eBook on The High Cost of Free Messaging Software.

The High Cost of Free Messaging Software

Weekly Email Marketing News Digest

Take a leaf out of the book of healthy living and apply it to your email lists. Just like you need to detox your body every now and then, email lists need to have the dust shaken off them and audited for quality control. Thats right – quality. While quantity does matter, the quality of your email lists is more vital as it has a direct impact on your sender score and thus deliverability. This week’s digest highlights ways to keep those lists clean, and grow them too.

Email Campaigns Flopping? It’s Probably Your List

If your email campaigns are flopping there is a good chance that your list isn’t as hygienic as you might think it is. Here’s a checklist:

How was your list acquired?

  • Did you buy it?
  • How long ago did subscribers join your list?
  • What did you promise them?

Have you kept your list clean?

  • Are you removing bad email addresses?
  • Have you reengaged inactive subscribers?

All the above factors play a part in determining the success of your campaign, so pay heed and keep your list healthy!

5 Tactics to Ignite Your Email List Growth

Here are 5 ways to spark list growth:

  1. Make it easy to opt in on your website.
  2. Don’t stop at just one.
  3. Collect email opt-in in your stores.
  4. Make it mobile.
  5. Remember your social networks.

For more details on ensuring the quality of your list as you grow it, hop on over to read the full article by Mike Hotz from Responsys.

Boost Conversion and Deliverability with 3 Email Marketing Rules

Here are three evergreen email marketing tips from the book, Email Marketing Rules: How to wear a white hat, shoot straight, and win hearts by Chad White from ExactTarget.

  1. Focus on maximizing the value of a subscriber, not on maximizing the results of a campaign. Don’t sacrifice the quality of your list for the sake of a one-off campaign by misleading subscribers.
  2. Don’t attach too much meaning to your open rates. The end goal of conversion is more important, hence gauge the success of your subject lines by that standard.
  3. Accept that ESPs have relatively little control over the deliverability of your emails. Sender reputation is the most important factor in deliverability and that’s related to the quality of your list.

3 Obsolete Email Practices

Email guru Loren McDonald recommends replacing three obsolete email practices.

  1. Annual reactivation campaigns – You can tell within a few months of a subscriber is unengaged so put them on a multi-step activation track. This helps ensure high quality lists too.
  2. Frequency testing – Use behavioral triggers instead.
  3. Single emails – Send a series of emails instead.

[Infographic] Email Marketing List Maintenance

Here’s a really cool flowchart on maintaining your email list.


I participated in a lively exchange online with some email industry colleagues recently around the topic of improving deliverability through permission-based lists versus data management techniques, such as list hygiene. My contention was that for years the industry has been hung-up on the term ‘permission’ – single opt-in, confirmed opt-in, double opt-in, etc. But at the end of the day, does permission really matter? (more…)