Should I block emails containing the word unsubscribe?

Summary

The overwhelming consensus from email marketing experts, documentation, and community discussions is that blocking emails solely based on the word "unsubscribe" is a poor strategy. It's unreliable, can block legitimate emails, and interferes with automated processes. Effective spam filtering relies on sender reputation, authentication protocols (SPF, DKIM, DMARC), reducing spam complaints through good email marketing practices, utilizing reputable ESPs, monitoring spam complaint rates, implementing feedback loops, creating safe sender lists, and employing comprehensive IP and domain-based blocklists. Building a quality email list through opt-in methods also significantly reduces the need for aggressive filtering. While blocking might stop some unwanted mail, the risk of false positives and the availability of better alternatives make it an undesirable approach.

Key findings

  • Unreliable: Keyword blocking is an unreliable method for filtering spam.
  • False Positives: Blocking emails with "unsubscribe" can block legitimate emails (false positives).
  • Better Alternatives Exist: Sender reputation, authentication, and engagement are more effective for filtering.
  • Interferes with Processes: Blocking based on header content (like List-Unsubscribe) can disrupt automated processes.
  • Legitimate Mail Missed: Many illegitimate emails do not contain the word "unsubscribe."

Key considerations

  • Sender Reputation: Prioritize building and maintaining a good sender reputation.
  • Authentication: Implement SPF, DKIM, and DMARC to authenticate your emails.
  • Engaged Subscribers: Focus on sending emails to engaged subscribers to reduce spam complaints.
  • Easy Unsubscribe: Provide clear and easy unsubscribe options for recipients.
  • Quality Email List: Build a high-quality email list through opt-in methods, avoiding purchased lists.
  • Monitoring: Monitor spam complaint rates and implement feedback loops.
  • Safe Senders List: Create a Safe Senders List to prevent blocking trusted contacts.
  • Aggressive Filtering: Avoid aggressive filtering that could block wanted emails.
  • Alternative Keywords: Consider blocking alternative phrases to "unsubscribe" but with extreme caution.
  • Balance: Weigh the potential benefits of blocking unwanted emails against the risk of blocking legitimate ones.
  • Holistic Approach: Take a holistic approach to email filtering, combining various techniques for optimal results.

What email marketers say
10Marketer opinions

The consensus among email marketers and experts is that blocking emails based solely on the presence of the word "unsubscribe" is not a recommended practice. While it might stop some unwanted cold outreach, it also risks blocking legitimate emails, including newsletters and important communications. More effective strategies focus on sender reputation, authentication protocols (SPF, DKIM, DMARC), reducing spam complaints through good email marketing practices (engaged subscribers, clear unsubscribe links, list segmentation), utilizing reputable ESPs with strong spam filters, educating recipients about marking emails as spam, and avoiding aggressive filtering that often catches wanted emails. Building a good email list through opt-in methods and avoiding spam traps are also recommended.

Key opinions

  • Blocking Risk: Blocking emails based on the word "unsubscribe" can lead to blocking legitimate emails.
  • Ineffective Solution: Keyword-based blocking is not an effective long-term solution for spam filtering.
  • Alternative Solutions: Sender reputation, authentication protocols (SPF, DKIM, DMARC), and reducing spam complaints are more effective spam filtering methods.
  • List Quality: Building a high-quality, opt-in email list reduces the need for aggressive spam filters.

Key considerations

  • False Positives: Aggressive filtering can lead to false positives, blocking desired emails.
  • Sender Reputation: Focus on sender reputation and authentication rather than content-based blocking.
  • Email Hygiene: Practice good email marketing hygiene, including clear unsubscribe links and list segmentation, to reduce spam complaints.
  • Alternative Filtering: Utilize a reputable ESP with strong spam filters rather than relying solely on keyword blocking.
  • Holistic Approach: Take a holistic approach to email filtering, combining various techniques for optimal results.
Marketer view

Email marketer from Email Geeks mentions they understand using the hammer approach to email filtering, especially when small organizations are overwhelmed by unwanted emails. They also use similar tactics with a text blocker app to stop political text messages.

May 2023 - Email Geeks
Marketer view

Email marketer from EmailOctopus Blog recommends against solely relying on keyword-based blocking. They suggest employing a combination of techniques such as using a reputable email service provider (ESP) with strong spam filters, educating recipients on how to mark emails as spam, and implementing proper email authentication protocols.

May 2024 - EmailOctopus Blog
Marketer view

Email marketer from Reddit's r/emailmarketing responds that blocking emails with "unsubscribe" is a bad idea as it will block legitimate newsletters. Focus on marking as spam and using filters based on sender.

January 2023 - Reddit
Marketer view

Email marketer from Sendinblue shares a list of ways to build a good list, which helps you not need aggressive filters. Start by using signup forms, not buying lists.

June 2023 - Sendinblue
Marketer view

Email marketer from Email Geeks shares that blocking the word "unsubscribe" will stop cold outreach in some cases, but not all, as not all cold outreach uses the word unsubscribe.

December 2022 - Email Geeks
Marketer view

Email marketer from Mailchimp highlights that focusing on reducing spam complaints is more effective than blocking specific keywords. They recommend practicing good email marketing hygiene, such as sending to engaged subscribers, using clear unsubscribe links, and segmenting lists.

April 2024 - Mailchimp
Marketer view

Email marketer from Litmus details avoiding spam traps, which is easier than blocking by word because you can send higher quality email. Use double opt-ins to start.

July 2024 - Litmus
Marketer view

Email marketer from Webmaster Forum shares that aggressive filtering almost always catches wanted emails. Recommends using a good spam filter instead.

June 2024 - Webmaster Forum
Marketer view

Email marketer from Neil Patel's Blog cautions against using simple keyword filters like "unsubscribe" to block emails, as legitimate emails may contain these words. He suggests focusing on sender reputation and authentication methods like SPF, DKIM, and DMARC for more effective spam filtering.

November 2022 - Neil Patel's Blog
Marketer view

Email marketer from StackExchange says blocking common words like "unsubscribe" will result in losing important emails. Whitelisting is better than blacklisting.

February 2025 - StackExchange

What the experts say
6Expert opinions

Experts generally advise against blocking emails solely based on the presence of the word "unsubscribe." While it may catch some unwanted emails, it can also block legitimate correspondence. Better filtering requires more complex and costly solutions. Keyword blocking is unreliable, and content filters can inadvertently block desired content. Prioritizing spam scoring offers a more effective alternative.

Key opinions

  • Oversimplification: Simple keyword blocking is not an adequate solution for effective email filtering.
  • Potential for False Positives: Content filters, including those targeting "unsubscribe," can block legitimate emails.
  • Better Alternatives: Spam scoring and more sophisticated filtering techniques offer more reliable alternatives.
  • Illegitimate Mail: Many illegitimate emails do not contain the word "unsubscribe."

Key considerations

  • Complexity: Good email filtering is a complex and expensive endeavor.
  • Alternative Keywords: Consider blocking alternative phrases, such as "to stop receiving," for emails that don't use "unsubscribe."
  • Balance: Weigh the potential benefits of blocking some unwanted emails against the risk of blocking legitimate ones.
  • Spam Scores: Filter by spam scores to reduce the amount of unwanted email more effectively.
Expert view

Expert from Email Geeks explains that blocking emails containing the word "unsubscribe" might block a tiny bit of real mail but would block a whole bunch of crap.

March 2022 - Email Geeks
Expert view

Expert from Word to the Wise explains that simple keyword blocking is a poor solution. Good filtering is difficult, expensive and complex.

October 2023 - Word to the Wise
Expert view

Expert from Email Geeks adds that countless illegitimate emails never use the word "unsubscribe".

August 2022 - Email Geeks
Expert view

Expert from Spam Resource states that content filters can block desired email content. Instead Spam Resource suggests filtering on spam scores to reduce unwanted email.

December 2023 - Spam Resource
Expert view

Expert from Email Geeks suggests that for emails without unsubscribe, perhaps blocking "to stop receiving" could be another approach.

November 2022 - Email Geeks
Expert view

Expert from Word to the Wise indicates the unreliability of blocking emails simply because of the presence of a word.

May 2024 - Word to the Wise

What the documentation says
5Technical articles

Email deliverability documentation sources consistently advise against blocking emails based solely on the presence of the word "unsubscribe." They advocate for more sophisticated methods like IP and domain reputation blocklists, Safe Senders Lists, feedback loops, and monitoring spam complaint rates. Blocking based on content alone can lead to false positives and interfere with legitimate automated email processes. Allowing users to easily unsubscribe is recommended instead.

Key findings

  • False Positives: Blocking based on content can result in blocking legitimate emails (false positives).
  • Ineffective Filtering: Simple keyword filtering is less effective than reputation-based blocklists.
  • Interference with Processes: Blocking based on header content can disrupt legitimate automated email processes.
  • Importance of Unsubscribe: Providing easy unsubscribe options is crucial and recommended.

Key considerations

  • IP/Domain Reputation: Use comprehensive blocklists based on IP addresses and domain reputations.
  • Safe Senders: Implement a Safe Senders List to prevent trusted sources from being blocked.
  • Feedback Loops: Establish feedback loops and monitor spam complaint rates.
  • Sophisticated Methods: Utilize more sophisticated filtering techniques than simple keyword blocking.
Technical article

Documentation from Cisco details the ways in which their system filters emails but highlights the importance of allowing users to unsubscribe from marketing emails, rather than blocking them.

June 2023 - Cisco
Technical article

Documentation from Microsoft details creating a Safe Senders List to ensure messages from trusted sources don't get blocked by aggressive filtering. Does not recommend keyword blocking.

October 2024 - Microsoft
Technical article

Documentation from Spamhaus advocates for using comprehensive blocklists based on IP addresses and domain reputations rather than simple keyword filtering. It suggests that blocking based on content can lead to false positives.

July 2023 - Spamhaus
Technical article

Documentation from ietf.org specifies the Internet Message Format, noting that while headers like "List-Unsubscribe" are commonly used for one-click unsubscription, blocking based on header content alone could interfere with legitimate automated email processes.

April 2023 - ietf.org
Technical article

Documentation from Google advises email senders to implement feedback loops and monitor spam complaint rates. They recommend providing easy unsubscribe options but don't suggest blocking based on the word "unsubscribe".

February 2022 - Google