Suppression lists filter out unengaged or risky contacts to maintain deliverability, which are essential for protecting a business’s sending reputation.
Yet, many companies fail to see them as a strategic asset, focusing instead on list growth or content engagement.
Brands that overlook their suppression lists risk sending to contacts who could harm their reputation, ultimately impacting their email campaign success.
In this interview, OPTIZMO COO Tom Wozniak discusses:
- The effectiveness of suppression lists management
- Why suppression list security matters for businesses
- The need to respect customer preferences and privacy in marketing campaigns
- Email compliance updates businesses must prepare for in 2025
Who Is Tom Wozniak?
Tom has over 25 years of experience in affiliate, email, display, video, and other forms of digital marketing. He regularly writes for Forbes.com and other industry publications and speaks on email marketing and compliance at various conferences. Before OPTIZMO, he was VP of Marketing at SpotX, headed up marketing at Media Breakaway, and held senior leadership roles with Trueffect and NextAction, among other companies.
Proactivity is key to your brand’s security.
“For some businesses, the only suppression files they are aware of are their opt-outs.
They know to follow the law and ensure that once a consumer has opted out of receiving future email marketing communications, they need to put that address on a suppression file to apply to future marketing campaigns.
But, that may be all they do,” Tom says.
He believes that this misses two major value propositions of strategic suppression list management:
- A great deal can be learned by analyzing opt-outs and looking for patterns in opt-out activity
- Suppression shouldn’t be limited to just opt-outs
Watch our video to learn what are triggered emails and how they can benefit your business:
How Effective Suppression Lists Management Drive Better Email Campaigns
Using suppression lists strategically can lead to higher overall campaign performance.
Hence, businesses should analyze their opt-outs for better targeting.
“Learning what aspects of your current email program may be driving a higher-than-normal opt-out rate can help you better plan future campaigns.
Looking at your opt-outs may help identify audience segments that you aren’t effectively communicating within your current campaign program.
By identifying them, you can create messaging designed to engage with these new segments more effectively, driving up overall performance,” Tom explains.
Additionally, he says that differentiating between prospective and existing customers improves the entire email marketing program.
“Even if you don’t have offers that are only available to new customers, chances are that the messaging you provide to existing vs. potential customers should differ.
You don’t have to win over an existing customer in the same way as a new one.
So, making sure you segment these two groups in your campaigns allows you to more effectively target each one with relevant offers and messaging,” he notes.
But how often should businesses audit and update their suppression lists?
Tom recommends that most suppression files should be dynamically updated on an ongoing basis, whereas unsubscribe lists should be updated each time a new opt-out request is received and processed.
Other suppression files, like existing customer files, should also be updated regularly as new customers are added, and potentially lapsed customers removed from the list, he advises.
“However, you may have other suppression lists that are created at a specific time, for a particular purpose.
Those more static lists should be audited or re-examined and updated on a fairly regular basis, typically lined up with your mailing frequency or how often that data changes,” he adds.
Tom highlights that automation is a key driver of efficiency when it comes to managing unsubscribe files.
“In particular, if you are using third parties (such as affiliates or performance agencies) to power your email marketing program, automation makes these programs scalable,” he explains.
He says that OPTIZMO automates both the collection of new unsubscribe requests generated by all of your mailing partners and then makes the updated suppression file(s) available for automatic distribution, all within a secure environment.
Without such a solution, this would all be a manual process, leading to potential human error, let alone poor data privacy practices.
SmartSites Co-Founder Michael Melen adds that businesses should also consider how they segment their lists to make suppression list management more efficient.
"Automatically sorting contacts by, for example, engagement or compliance status, will enable companies to send more targeted and effective emails. This reduces the risk of human error and frees up teams to focus on strategies.
Additionally, the process can scale as the business grows. Brand reputation stays protected while email effectiveness improves," he says.
Tom shares OPTIZMO’s case study on Publishers Clearing House (PCH) which faced the challenge of managing complex email suppression lists while ensuring compliance with privacy regulations like CAN-SPAM.
OPTIZMO automated platform helped streamline the updating, distribution, and encryption of suppression files, saving time and resources and ultimately leading to optimized email marketing campaigns and business growth.
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The Importance of Suppression List Security
Effective suppression list management ensures compliance with data privacy regulations.
This helps businesses enhance their campaigns while maintaining secure and targeted communications.
“Management of your opt-out data falls directly in line with data privacy laws and practices.
It’s a requirement in any state or country that requires businesses to provide consumers with a way to opt out of future marketing communications or otherwise have their personal data removed from a company’s database,” Tom explains.
He highlights that as with any database, suppression files should be protected by a robust data security program.
“Whether it’s a company’s internal databases or those stored by vendors or technology partners, it’s important to audit the security processes and procedures in place to keep those databases secure.
This may involve a detailed review of a company’s data security program or ensuring that they have been assessed by a group like the Cloud Security Alliance to validate a company’s security practices and processes,” he adds.
Respecting Customer Privacy While Optimizing Marketing Campaigns
Respecting customer privacy can enhance marketing success.
It made me question how businesses can effectively balance their marketing efforts with the need to respect customer preferences and privacy.
Respecting customer data privacy preferences and marketing campaign optimization actually work very well together, Tom answers.
“Following customer data privacy requests is not only the law but also can only help your marketing program.
When a consumer opts out of future marketing communications, they are also self-identifying as someone who was highly unlikely to ever respond to your campaigns,” he explains.
Hence, businesses shouldn’t waste their marketing budgets trying to engage with consumers who will never become customers.
“Then, learning from consumers who opt out, companies can identify ways to more effectively engage with all of their audience segments,” Tom concludes.
Changing Guidelines Are Shaping the Future of Email Opt-Outs
Moving into 2025, Tom says that businesses should be aware of the changing requirements of inbox providers for companies sending larger volumes of email (5,000+) on a daily basis.
“In order to have their emails delivered, these companies now need to adopt stricter domain authentication processes, offer specific unsubscribe options, and process opt-out requests more quickly than current federal law requires,” he says.
He shares that many email marketing platforms have adopted the new guidelines for all their clients, rather than just higher volume email senders.
“The guidelines are all fairly straightforward for companies to follow, but ignoring them could have negative impacts on your email marketing program,” he concludes.
Strategic suppression list management is important for business compliance and security.
However, it also helps maximize the effectiveness of email marketing campaigns and protect a brand’s reputation.
