Summary
The overwhelming consensus from email marketing experts, documentation, and community discussions is that validating email addresses based on open activity from other senders is generally not possible, advisable, or ethical. This is primarily due to technical limitations, privacy concerns (including potential GDPR violations), and the intrusive nature of such tracking. While limited solutions like Experian's Email Insights co-op exist, they require contributing data and don't offer direct access to cross-sender activity. The recommended approach involves focusing on robust list hygiene practices, building a strong sender reputation, and ensuring transparency and compliance with privacy regulations.
Key findings
- Impossibility/Infeasibility: It is generally impossible or infeasible to reliably track email open activity across different senders due to technical and practical limitations.
- Privacy Violations: Tracking open activity across senders raises significant privacy concerns and may violate regulations like GDPR.
- Ethical Concerns: Such tracking methods are often considered intrusive and unethical due to the lack of explicit consent.
- Limited Solutions: Existing solutions (e.g., data co-ops) have limitations and require contributing data, not just accessing it.
- Technical Barriers: Email clients and tracking mechanisms typically prevent cross-sender open tracking.
Key considerations
- List Hygiene: Implement robust list hygiene practices, including double opt-in, regular cleaning, and removing inactive subscribers.
- Sender Reputation: Focus on building and maintaining a strong sender reputation to improve deliverability.
- Privacy Compliance: Ensure compliance with privacy regulations such as GDPR and be transparent with subscribers about data practices.
- Ethical Practices: Adopt ethical email marketing practices that respect user privacy and consent.
- Alternative Validation: Use ethical and compliant email validation methods that focus on syntax, domain, and deliverability rather than cross-sender tracking.
What email marketers say
11 marketer opinions
The consensus among email marketing experts is that validating email addresses based on open activity from other senders is generally not possible due to a combination of technical limitations, privacy concerns, and ethical considerations. While some solutions like Experian's 'Email Insights' co-op exist, they require contributing your own data and don't directly share email addresses. The emphasis is placed on employing standard list hygiene practices such as double opt-in, regular list cleaning, and focusing on sender reputation and engagement metrics.
Key opinions
- Impossibility: It is practically impossible to reliably track email open activity across different senders due to technical restrictions and privacy safeguards.
- Privacy Concerns: Attempting to track open activity across senders raises significant privacy concerns and may violate GDPR or other data protection regulations.
- Ethical Issues: Such practices are often considered intrusive and unethical, as they involve tracking user behavior without explicit consent.
- Limited Solutions: While some co-op databases exist (e.g., Experian's Email Insights), they require sharing your own data and do not provide access to external open activity.
- Alternative Methods: Email validation services primarily focus on syntax checks, domain validation, and spam trap detection, rather than tracking open activity.
Key considerations
- Focus on Hygiene: Prioritize list hygiene best practices such as double opt-in, regular list cleaning, and removing inactive subscribers.
- Sender Reputation: Concentrate on building and maintaining a strong sender reputation to improve email deliverability.
- Engagement Metrics: Focus on improving your own sending practices and engagement metrics (opens, clicks) to optimize email performance.
- Privacy Compliance: Ensure that all email marketing practices comply with relevant privacy regulations (e.g., GDPR, CCPA).
- Transparent Communication: Be transparent with subscribers about how their data is being collected and used.
Marketer view
Email marketer from EmailToolTester responds that knowing with certainty if someone is active on other senders' lists is impossible and that they promote focusing on your own sending practices and engagement metrics.
11 Sep 2022 - EmailToolTester
Marketer view
Marketer from Email Geeks explains that while technically possible through data sharing and fingerprinting, it's intrusive and goes against privacy safeguards.
25 Jul 2021 - Email Geeks
What the experts say
1 expert opinions
According to an expert from Word to the Wise, validating email addresses based on open activity from other senders is generally not feasible or advisable due to significant privacy concerns and technical limitations in email tracking and data sharing.
Key opinions
- Not Feasible: Validating email addresses based on cross-sender open activity is generally not feasible.
- Privacy Concerns: The practice raises significant privacy concerns.
- Technical Limitations: Technical limitations in email tracking and data sharing make it unlikely to be possible.
Key considerations
- Alternative Validation: Focus on alternative email validation methods that respect privacy.
- Ethical Practices: Prioritize ethical email marketing practices and respect user privacy.
Expert view
Expert from Word to the Wise answers that attempting to validate email addresses based on open activity across different senders is generally not feasible or advisable. She states that it raises significant privacy concerns and is unlikely to be technically possible due to the limitations of email tracking mechanisms and data sharing restrictions.
1 Apr 2025 - Word to the Wise
What the documentation says
3 technical articles
Documentation from IETF, Litmus, and GDPR collectively indicates that validating email addresses based on open activity from other senders is technically challenging, ethically questionable, and likely in violation of GDPR. Standard email tracking methods are limited to the sender's own emails, and cross-sender tracking is blocked for privacy reasons.
Key findings
- Technically Challenging: Tracking open activity across different senders is technically challenging.
- Ethically Questionable: Tracking without explicit consent raises ethical concerns.
- GDPR Violation: Collecting and sharing such data likely violates GDPR.
- Tracking Limitations: Standard tracking methods are limited to the sender's own emails.
- Privacy Blocked: Cross-sender tracking is generally blocked by email clients for privacy.
Key considerations
- Privacy Compliance: Ensure all email marketing practices comply with GDPR and other privacy regulations.
- Alternative Validation: Focus on ethical and compliant email validation methods.
- Transparency: Be transparent with subscribers about data collection and usage.
Technical article
Documentation from Litmus explains that standard email tracking methods, like pixel tracking, can only confirm opens for emails sent by the tracker's owner. Tracking across different senders is not a supported feature and is generally blocked by email clients for privacy reasons.
18 Jan 2023 - Litmus
Technical article
Documentation from ietf.org discusses the privacy considerations surrounding email communication. It answers that it is technically challenging and ethically questionable to track open activity across different senders without explicit consent, reinforcing the limitations of such validation methods.
28 Aug 2022 - ietf.org
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