Summary
Sending a one-time email to a large list of inactive users is a complex undertaking with considerable risks. Experts generally advise against it, suggesting alternative communication methods like in-app notifications or sunsetting accounts per the AUP. If email is necessary, involve legal, technical, and business teams to address compliance and data ownership. Essential practices include segmenting the list, warming up the IP, cleaning the list, using SPF/DKIM/DMARC, including a List-Unsubscribe header, monitoring sender reputation, throttling sending speed, personalizing content, and A/B testing. Third-party services may be an option for mandatory notifications. Ultimately, careful planning and execution are crucial to minimize harm to sender reputation and deliverability.
Key findings
- Risk Mitigation: Sending to inactive users poses significant risks to sender reputation and deliverability.
- Alternative Channels: Explore alternative communication channels before resorting to email.
- Legal Compliance: Ensure legal compliance regarding data possession and notification requirements.
- Technical Setup: Proper email authentication (SPF, DKIM, DMARC) is essential.
- Hygiene & Sunset: List cleaning and implementing a sunset policy are critical for list maintenance.
- Reputation Monitoring: Monitoring sender and domain reputation helps identify deliverability issues.
Key considerations
- Segmentation: Segment the inactive list for tailored re-engagement efforts.
- Warming Up: Gradually warm up the IP address to establish a positive sender reputation.
- Content: Create compelling and personalized content to increase engagement.
- Third-Party: Consider using a third-party service for legally mandated notifications.
- AUP Review: Review and update your AUP to address inactive accounts and data retention.
What email marketers say
11 marketer opinions
Sending a one-time email to a large list of inactive users requires careful planning to avoid deliverability issues and maximize re-engagement. Key strategies include segmenting the list to isolate inactive users, warming up your IP address by gradually increasing sending volume, and cleaning the list to remove invalid addresses. Creating compelling and personalized content, A/B testing subject lines and email content, and previewing the email across different clients are crucial for improving engagement. Throttling sending speed, implementing easy unsubscribe processes, and considering using a third-party service for mandatory notifications can further protect your sender reputation and ensure compliance.
Key opinions
- Segmentation: Segmenting inactive users allows for tailored re-engagement strategies or removal from active lists.
- IP Warmup: Warming up the IP address is essential when sending to large lists to establish a positive sender reputation.
- Content: Creating compelling and personalized content is vital for re-engaging inactive users.
- List Cleaning: Prioritizing cleaning the email list reduces bounce rates and protects sender reputation.
- Throttling: Throttling sending speed prevents being flagged as a spammer.
- A/B Testing: A/B testing optimizes re-engagement efforts and improves response rates.
- Previewing: Previewing emails ensures correct rendering across various clients and devices.
- Unsubscribe: Make unsubscribing easy to avoid spam complaints.
Key considerations
- Third-party service: Consider a third-party service for mandatory notifications to manage sending and compliance.
- Legal Classification: Determine if the email qualifies as a mandatory notification based on legal requirements.
- Personalization: Personalize emails based on subscriber past actions.
- Signup Forms: Use reCAPTCHA on signup forms to prevent fake/invalid emails.
Marketer view
Email marketer from StackOverflow explains to prioritize cleaning your email list before sending any emails. Removing invalid or non-existent email addresses will significantly reduce bounce rates and protect your sender reputation.
6 Aug 2022 - StackOverflow
Marketer view
Email marketer from Mailjet Blog explains that segmenting your list to isolate inactive users is crucial. By identifying those who haven't engaged in a while, you can tailor your one-time email to re-engage them or remove them from your active list to improve deliverability.
16 Aug 2023 - Mailjet Blog
What the experts say
14 expert opinions
Sending a one-time email to a large list of inactive users carries significant risks to your sender reputation and deliverability. Experts strongly advise exploring alternative communication methods, such as in-app notifications. If email is unavoidable, involve legal and technical teams to ensure compliance and consider the justification for possessing inactive user data. Cleaning the email list, implementing a sunset policy, and monitoring sender reputation are crucial. Gradual volume increases, personalization, and testing are beneficial. Sending to inactive users should be approached cautiously, if at all, due to the high potential for negative impact.
Key opinions
- Damage Risk: Sending emails to unengaged users can severely damage regular mail streams.
- Alternative Methods: Consider alternative communication methods before resorting to email.
- Legal Review: Involve legal teams to justify possessing PII for inactive users.
- Sunset Policy: Implement a sunset policy to automatically suppress or unsubscribe inactive users.
- List Hygiene: Maintaining strict list hygiene is critical for mitigating deliverability risks.
- Domain Reputation: Checking your sending domain reputation helps avoid blocklists.
Key considerations
- ESP Approval: Legitimate ESPs are unlikely to allow sending to lists with dubious permission.
- Customer Status: Inactive users who aren't logging in may no longer be considered customers.
- Volume Threshold: Control email volume to not hurt email deliverability.
- Sunset AUP: Implement a sunset period in AUP for cleaning lists
- Sender Reputation: Review your sender reputation.
Expert view
Expert from SpamResource emphasizes maintaining strict email list hygiene, including regular cleaning and suppression of invalid addresses, to mitigate deliverability risks when sending to inactive users. They explain invalid emails are a major reason for bounces and spam complaints.
19 Nov 2023 - SpamResource
Expert view
Expert from Email Geeks says that she doesn’t know of any legitimate ESP that will let you come up with a list of stale addresses that you have dubious permission to mail and let you send one message because there is too much risk to their infrastructure and it could lead to suspension for spamming.
23 May 2025 - Email Geeks
What the documentation says
3 technical articles
When sending a one-time email to a large list of inactive users, it's crucial to follow email authentication best practices and monitor your sender reputation. Implementing SPF, DKIM, and DMARC helps verify your identity and reduce the likelihood of being marked as spam. Including a List-Unsubscribe header provides recipients with an easy way to opt-out, reducing spam complaints and improving your reputation. Monitoring tools like Sender Score and Microsoft's SNDS can help identify and address deliverability issues before sending.
Key findings
- Authentication: SPF, DKIM, and DMARC are essential for authenticating your email and improving deliverability.
- List-Unsubscribe: A List-Unsubscribe header reduces spam complaints and improves sender reputation.
- Monitoring: Regularly monitor your sender reputation to identify and address deliverability issues.
Key considerations
- Bulk Sender Guidelines: Adhere to Gmail's bulk sender guidelines to avoid deliverability problems.
- Spam Complaint Rate: Maintain a low spam complaint rate to protect your sender reputation.
- Proactive Identification: Proactively identify and address deliverability issues before sending to a large list.
Technical article
Documentation from Gmail Help emphasizes adhering to Gmail's bulk sender guidelines. This includes setting up authentication methods like SPF, DKIM, and DMARC, as well as ensuring a low spam complaint rate to avoid deliverability issues.
24 Dec 2023 - Gmail Help
Technical article
Documentation from Microsoft discusses monitoring your sender reputation through tools like Sender Score and Microsoft's SNDS to identify and address any issues that could impact deliverability before sending to a large list of inactive users.
28 Jul 2022 - Microsoft
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