Are cold outreach 'best practices' actually illegal spam tactics?
Michael Ko
Co-founder & CEO, Suped
Published 14 May 2025
Updated 16 Aug 2025
9 min read
The world of cold outreach is often seen through a different lens by various teams within an organization. For a sales development representative (SDR) team, "deliverability" might mean getting emails past initial filters, even if it involves aggressive tactics. For a compliance team, it's about adhering strictly to regulations like the CAN-SPAM Act. This disparity leads to a crucial question: are some widely adopted cold outreach "best practices" actually illegal spam tactics in disguise?
Many approaches promoted for high volume cold emailing contradict established norms for healthy email ecosystems. These often prioritize short-term gains over long-term sender reputation and deliverability, risking not just inbox placement but also legal repercussions and potential blocklisting (or blacklisting). Let's explore the lines being blurred and what genuinely constitutes compliant, effective cold outreach.
The blurred line between cold outreach and spam
A common strategy in some cold outreach circles involves using multiple "burner" domains and inboxes for each SDR. The idea is to distribute sending volume, acting as backups in case one domain’s reputation is compromised. Software platforms even exist to centralize these inboxes and automatically rotate sending, with some users reportedly rotating across ten or more domains. While seemingly a clever way to bypass immediate blocks, this practice closely mirrors methods used by spammers and significantly impacts overall domain reputation.
Another tactic promoted is to remove traditional unsubscribe links from cold emails and replace them with a "reply to opt out" instruction. The reasoning often cited is that links can increase the likelihood of emails landing in spam folders, while replies are seen as a positive engagement signal by email service providers (ESPs). However, this interpretation often misaligns with legal compliance and standard email marketing best practices. It places an unnecessary burden on the recipient and can lead to frustration, increasing spam complaints.
Additionally, some cold outreach software utilizes AI to rotate content and make automated emails appear more human. While personalization is valuable, using AI purely to evade spam filters by constantly changing text patterns without genuine relevance can be counterproductive. ESPs are becoming increasingly sophisticated at identifying these tactics. Focusing on delivering genuinely valuable and targeted content is far more effective in the long run than trying to outsmart filters through automation. This type of activity often contributes to emails being sent to the spam folder.
The risks of aggressive cold outreach
Employing tactics like burner domains, omitting standard unsubscribe links, and using AI for content obfuscation can lead to severe consequences. These practices can result in your domains being flagged by email providers like Google or Microsoft, damaging your sender reputation and leading to widespread email deliverability issues. Your messages are more likely to be sent to the spam folder or rejected entirely. Furthermore, these methods often violate anti-spam laws, exposing your business to significant legal and financial penalties.
Regulatory compliance and the CAN-SPAM Act
While the term "spam" often carries a negative connotation, its legal definition can vary by jurisdiction. In the United States, the CAN-SPAM Act of 2003 sets the rules for commercial email. Crucially, it doesn't ban cold emails outright, but it does mandate certain requirements. For instance, it requires that recipients be provided a clear and conspicuous way to opt out of receiving future emails, and that opt-out requests be honored promptly. The argument that a "reply to opt out" complies with this can be misleading, as the law specifies an unsubscribe mechanism that is "easy" for the recipient. You can learn more about CAN-SPAM compliance from the Federal Trade Commission. While cold emailing is not inherently illegal, it must follow specific laws to avoid penalties. You can refer to this guide from Nureply for more insights.
Beyond CAN-SPAM, other significant regulations include the GDPR in Europe and Canada's Anti-Spam Legislation (CASL). These laws are often stricter, emphasizing explicit consent before sending commercial electronic messages. Relying on implied consent or simply offering a "reply to opt out" can fall short of these international standards, potentially leading to substantial fines and legal challenges. This is why it's vital to differentiate between legitimate cold email and what is commonly regarded as spam.
Many of these tactics also fall under the category of "unprofessional email marketing tactics" that can lead to spam reports. It's not just about what's legally allowed, but also about building a positive sender reputation. For more on this, check out our guide on unprofessional email marketing tactics. Remember, the goal is to build relationships, not just to bypass filters. A "reply to opt out" instruction might appear as a loophole but often misses the spirit of anti-spam laws and can be seen as an attempt to avoid legitimate unsubscribe practices. Always aim for a clear, one-click unsubscribe option. Here's how a compliant unsubscribe link would typically look versus the problematic "reply to opt out".
Compliant unsubscribe link
Provides a direct, automated way for recipients to opt out of future emails. This is usually a single-click link.
Example footerplaintext
To unsubscribe, click here: [Unsubscribe Link]
Non-compliant or problematic "reply to opt out"
Requires manual action from the recipient, which can be seen as an unnecessary barrier. It relies on the sender actively processing replies.
Example footerplaintext
To opt out of future emails, simply reply to this message with "Unsubscribe".
Here is a comparison of key anti-spam regulations pertinent to cold outreach:
Regulation
Jurisdiction
Key requirements for cold email
CAN-SPAM Act
United States
Clear sender identification, accurate subject lines, physical postal address, clear and easy opt-out mechanism, honor opt-out requests promptly. No pre-checked opt-in boxes.
GDPR (General Data Protection Regulation)
European Union (EU) and EEA
Requires explicit, unambiguous consent for processing personal data, including email addresses for marketing. Opt-out must be easy and free. Stricter rules for unsolicited emails.
CASL (Canada's Anti-Spam Legislation)
Canada
Requires express or implied consent to send commercial electronic messages. Clear identification of sender, contact information, and an unsubscribe mechanism. Higher bar for implied consent than CAN-SPAM.
Impact on sender reputation and deliverability
The impact of aggressive cold outreach extends beyond legal compliance to directly affect your email domain reputation. Email providers heavily weigh sender reputation when deciding whether to deliver emails to the inbox or divert them to spam. Tactics such as high volume sending from new or frequently rotated domains, low engagement rates, and high spam complaint rates can quickly degrade your reputation. Once your domain's reputation suffers, it can be a lengthy and challenging process to rebuild it. This is why it's so important to monitor your blocklist status.
Using "burner" domains, or frequently abandoning domains once they accrue negative reputation, leads to a never-ending cycle of domain warm-up and burning. This is not a sustainable strategy and indicates to ESPs that you are engaging in problematic sending behavior. Email service providers are continuously improving their algorithms to detect and penalize senders who employ these types of evasive tactics. What might have worked in 2018 is likely far less effective and more damaging in 2024 or 2025.
The long-term consequence is that your emails, even legitimate ones, may consistently fail to reach the inbox. This can severely hinder your sales and marketing efforts. Preventing your domains or IP addresses from appearing on a blacklist (or blocklist) is far easier than trying to get them delisted once a poor reputation is established. For strategies on proper domain warm-up, consider reviewing our guide on domain warm-up strategies to avoid spam filters.
Sustainable cold outreach strategy
Instead of focusing on short-term evasive maneuvers, a sustainable cold outreach strategy prioritizes building a strong, lasting sender reputation. This means adhering to best practices, even if they seem to slow down initial outreach volume. It involves ensuring your emails are highly targeted and relevant to the recipient, reducing the likelihood of spam complaints and increasing positive engagement like replies and opens. Focusing on a long-term strategy can also help avoid issues like account shutdowns from major email providers.
Key components of a robust, compliant, and deliverable cold email strategy include meticulous list hygiene, proper email authentication (SPF, DKIM, DMARC), and a clear, easy-to-use unsubscribe option. Automated list management, including processing opt-out requests promptly across all related sending entities, is crucial for compliance. Understanding and implementing these protocols is foundational for good deliverability. We have a simple guide to DMARC, SPF, and DKIM that can help.
Ultimately, the effectiveness of cold outreach should be measured not by the volume sent, but by the quality of engagement and conversions it generates. A lower volume of highly targeted, personalized, and compliant emails will yield far better results and preserve your sender reputation than a high volume of borderline spam. Prioritizing long-term relationship building over immediate, potentially illicit, gains is key for sustainable growth. Consider the long-term impact on your business's overall brand and how recipients perceive your communication. For more on this, consider reading our advice on company prioritization of short-term gains.
Embrace genuine best practices
By shifting from aggressive, potentially illegal tactics to transparent, consent-driven email practices, you not only ensure compliance but also foster better relationships with prospects. This approach yields higher quality leads, improves conversion rates, and safeguards your sender reputation for the long haul. Remember, email deliverability is a marathon, not a sprint.
Views from the trenches
Best practices
Focus on highly targeted, personalized emails to genuinely interested prospects.
Implement a clear, one-click unsubscribe mechanism in all commercial emails.
Maintain meticulous list hygiene to avoid stale or invalid email addresses.
Regularly monitor your domain and IP reputation using tools and dashboards.
Prioritize building long-term relationships over short-term volume gains.
Common pitfalls
Using multiple 'burner' domains and inboxes to evade detection.
Replacing unsubscribe links with 'reply to opt out' instructions.
Purchasing or scraping email lists without explicit consent.
Employing AI solely for content spinning to bypass spam filters.
Ignoring local and international anti-spam legislation like GDPR or CASL.
Expert tips
Email service providers are constantly evolving to detect and block evasive tactics.
Companies often prioritize immediate cash flow over long-term customer lifetime value.
A single bad cold email campaign can significantly damage your domain's reputation.
Some cold outreach tools actively encourage practices that lead to blocklisting.
Legitimate email marketers suffer when the channel is flooded with spam.
Marketer view
A multi-domain and multi-inbox strategy for SDRs, where sending volume is split across numerous burner domains and inboxes, is being promoted. This often involves software that centralizes these and automatically rotates sending, sometimes across 10 domains, with AI rotating content to make automated emails seem more human.
2023-03-16 - Email Geeks
Marketer view
The industry teaches senders how to be spammers, which is detrimental to overall email ecosystem health.
2023-03-16 - Email Geeks
Navigating the compliance landscape
The distinction between cold outreach and spam is critical, both legally and for maintaining a healthy email program. While cold emailing can be a legitimate sales tool, the so-called "best practices" that involve tactics like burner domains, deceptive content rotation, or non-compliant opt-out methods are, in essence, spam tactics. They undermine trust, harm sender reputation, and can lead to severe penalties.
For long-term success, focus on building legitimate relationships. This means highly targeted messages, clear communication, robust email authentication, and straightforward unsubscribe processes. Adhering to these principles will ensure your outreach is effective, compliant, and sustainable, delivering real value rather than just hitting inboxes. Investing in proper email deliverability ensures your messages reach their intended audience without resorting to tactics that cross ethical or legal lines.
Google or 
Microsoft, damaging your sender reputation and leading to widespread email deliverability issues. Your messages are more likely to be sent to the spam folder or rejected entirely. Furthermore, these methods often violate anti-spam laws, exposing your business to significant legal and financial penalties.
