Summary
Experts, marketers, and documentation sources converge on the understanding that seed lists have limited accuracy for email deliverability testing in today's email ecosystem. Mailbox providers employ personalized, adaptive algorithms, rendering seed list results less reflective of real user experiences. Seed lists often exhibit different access and delivery patterns and can be easily identified by ISPs. While they may offer insights into broad trends or major issues, they should not serve as the sole measure of deliverability. Validating email authentication (SPF, DKIM, DMARC), monitoring sender reputation via tools like Google Postmaster Tools and Microsoft SNDS/JMRP, and real-world testing with representative audiences provide more reliable assessments.
Key findings
- Inaccurate Reflection: Seed lists fail to accurately mirror real-world email delivery due to personalized filtering and evolving algorithms.
- Historical Value: Seed lists have diminished in value due to provider algorithm updates.
- Identifiable Patterns: Seed list mailboxes are easily recognizable, leading to biased filter behavior.
- Limited Scope: Seed lists provide a restricted view, failing to incorporate real user behavior or dynamic ISP rules.
- Authentication Effects: SPF, DKIM and DMARC standards and configurations directly impact seed list testing outcomes and data reliability.
Key considerations
- Personal Testing: Prioritize testing using personal email accounts for more reliable feedback.
- Algo Awareness: Acknowledge ongoing changes in mailbox provider algorithms and adapt testing strategies accordingly.
- Comprehensive Evaluation: Integrate seed lists as a component of a broader testing and monitoring approach.
- Reputation Monitoring: Proactively monitor sender and IP reputation via available tools to track deliverability performance.
- Authentication Protocol: Prioritize full authentication by adopting SPF, DKIM and DMARC email authentication protocols.
What email marketers say
12 marketer opinions
Experts and marketers generally agree that seed lists offer a limited and potentially misleading view of email deliverability. While they can provide directional insights and help identify major issues, the increasing personalization of inbox placement decisions by mailbox providers, coupled with evolving filtering algorithms, makes seed list results less representative of real-world email delivery. Factors like engagement history, IP reputation, and content all influence seed list accuracy. A combination of methods, including feedback loops, authentication protocols, real-world testing, and monitoring sender reputation, is recommended for a comprehensive understanding of deliverability.
Key opinions
- Limited Accuracy: Seed lists don't fully reflect real-world email delivery due to personalized inbox placement decisions.
- Evolving Algorithms: Mailbox providers' filtering algorithms are constantly changing, impacting seed list reliability.
- Misleading Results: Seed lists can be misleading if used to 'game' promotional folder placement, as algorithms are complex.
- Directional Insights: Seed lists can provide a starting point or directional insights, but should not be the definitive answer.
- Not Definitive: Seed lists cannot be considered a definitive measure of deliverability to individual users.
Key considerations
- Combine Methods: Use seed lists in combination with feedback loops, authentication protocols, and real-world testing.
- Engagement History: Consider the engagement history of seed accounts, as it affects their behavior.
- IP Reputation: Factor in your IP address reputation, which influences how seed lists perceive your emails.
- Authentication: Ensure proper email authentication (SPF, DKIM, DMARC) for accurate seed list results.
- Monitor Reputation: Monitor your sender reputation through tools like Google Postmaster Tools for a better understanding of deliverability.
Marketer view
Marketer from Email Geeks explains that many moons ago, they used to run a service for seedlist testing mail delivery trends. They discontinued it after mailbox providers evolved in how they made their inbox/spam decisions based on per recipient choices and those seed lists were no longer representative of how real world emails were delivered.
6 Apr 2022 - Email Geeks
Marketer view
Email marketer from Reddit explains that seed lists are a starting point, but real-world results can vary due to user engagement and filtering algorithms. They are best used for directional insights, not definitive answers.
13 Oct 2021 - Reddit
What the experts say
8 expert opinions
Experts largely agree that seed lists have limited accuracy for email deliverability testing in the modern email landscape. Mailbox providers use personalized and adaptive algorithms, making seed list results less representative of real user experiences. Seed lists often have different access and delivery patterns than real mailboxes and are easily identifiable. While seed lists can show trends, they should not be the sole basis for evaluating deliverability. Testing with personal accounts provides more realistic insights.
Key opinions
- Limited Accuracy: Seed lists are not accurate due to personalized algorithms and different delivery patterns compared to real mailboxes.
- Outdated Value: Seed lists had value historically, but are now less relevant for consumer providers.
- Easily Recognizable: Seed list mailboxes are easily identifiable, causing different treatment by filters.
- Limited View: Seed lists provide a limited view of deliverability, not reflecting real user behavior or changing ISP rules.
- Trend Indication: Seed lists can help identify trends, but should not be the only factor considered.
Key considerations
- Personal Accounts: Testing with personal email accounts is more useful than commercial seed lists.
- Algorithm Changes: Be aware that mailbox provider algorithms are constantly evolving, impacting seed list accuracy.
- Snake Oil: Be cautious of deliverability advice that doesn't account for per-recipient decision-making by ISPs.
- Combined Approach: Avoid relying solely on seed lists; consider other factors and testing methods.
- Promotions Tab: Understand that optimizing for the promotions tab is difficult due to complex and evolving algorithms.
Expert view
Expert from Email Geeks explains a good thing to spot snake oil is to remember that modern B2C ISPs have a lot of decision making about mail delivery that’s specific to the recipient. States if you're testing delivery to a particular email address, that doesn’t necessarily mean anything about delivery to other email addresses, particularly ones used by real users rather than test or seed addresses, and if you repeatedly send mail to an address that affects the per-recipient decision making for that address, so even if the first and tenth mails to it you send are identical they will be treated differently. Concludes if the article is based on those things not being true, and it doesn’t address those issues, it’s snake oil.
6 Oct 2021 - Email Geeks
Expert view
Expert from Email Geeks explains that people have been trying to figure out the Promotions Algorithm for almost a decade now. The fact that we don’t have clear best practices (the way we do with the spam filter) tells you all you need to know about how easy it is to put mail in the tab you want it in.
9 May 2023 - Email Geeks
What the documentation says
5 technical articles
Technical documentation emphasizes that proper email authentication (SPF, DKIM, DMARC) and monitoring sender reputation are crucial for email deliverability, impacting how seed lists perceive email streams. Tools like Google Postmaster Tools, Microsoft SNDS, and JMRP offer more accurate insights into deliverability issues than relying solely on seed lists.
Key findings
- Authentication Matters: Validating SPF records, signing with DKIM, and enforcing DMARC policies are essential for email authentication and deliverability.
- Reputation Impacts: Sender reputation directly influences email deliverability and how seed lists perceive emails.
- Limited Seed Lists: Seed lists alone provide an incomplete picture of deliverability problems.
- Authentication Impact: Seed list results are impacted by DKIM signing.
- DMARC Importance: Seed lists are impacted by DMARC.
Key considerations
- Validate SPF: Ensure SPF records are correctly set up and validated for proper email authentication.
- Implement DKIM: Implement DKIM signing to improve deliverability and build trust with mailbox providers.
- Enforce DMARC: Enforce DMARC policies to prevent email spoofing and improve deliverability reporting.
- Monitor Tools: Use tools like Google Postmaster Tools and Microsoft SNDS/JMRP to monitor sender and domain reputation.
- Authentication Impact: Implement authentication standards like DMARC, DKIM and SPF to improve seed list outcomes.
Technical article
Documentation from Microsoft recommends using Smart Network Data Services (SNDS) and the Junk Mail Reporting Program (JMRP) to monitor your IP and domain reputation. These can give a more accurate picture of deliverability problems than seed lists.
28 Jul 2022 - Microsoft
Technical article
Documentation from RFC Editor specifies that SPF (Sender Policy Framework) records should be validated during deliverability testing to ensure proper email authentication, which affects placement.
7 Apr 2024 - RFC Editor
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