When can I include event attendees in an email warming list?

Key findings

• Consent is critical: Event attendance, whether virtual or physical, does not inherently grant explicit permission for general marketing emails. Proper consent for each email type is essential.
• High risk lists: Lists of event attendees who have not explicitly opted in for ongoing marketing communications are considered high risk for warming, as they are more likely to generate complaints.
• Post-ramp-up integration: Any prospect lists with less certain engagement or consent should only be introduced to your sending stream after your email sender reputation is established and stable.
• Incremental addition: When incorporating these less engaged contacts, it is best to do so in small, controlled increments to minimize any potential negative impact on your deliverability.
• Engagement focus: Email warming relies on positive engagement signals, which are less likely to come from contacts whose primary interaction was event attendance, not email subscription.

Key considerations

• Explicit opt-in: Always prioritize obtaining clear, documented, and explicit consent for marketing emails, ideally through a double opt-in process.
• List segmentation: Keep event attendee lists separate from your primary engaged audience until you have secured proper marketing consent.
• Monitor metrics: Closely monitor your email metrics, such as complaint rates, bounce rates, and unsubscribe rates, after introducing any new segments.
• Compliance awareness: Understand the legal and ethical implications of emailing event attendees, particularly regarding consent and data privacy regulations.
• Brand reputation: Unwanted emails can quickly lead to negative sentiment and damage your brand's reputation with recipients and ISPs alike.

Key opinions

• Consent imperative: Many marketers assert that explicit, voluntary consent is the cornerstone for any email list used for marketing purposes, particularly for warming.
• Risky populations: Attendees of webinars, virtual events, or physical tradeshows are often considered risky for direct inclusion in a warming list unless specific consent for email marketing was obtained during registration.
• Complaint concerns: A primary concern is that sending to event attendees without explicit opt-in can lead to a high volume of spam complaints, damaging sender reputation.
• Ramp-up strategy: Marketers generally agree that the initial email warming ramp-up phase should be conducted exclusively with highly engaged, clearly opted-in subscribers.
• Incremental introduction: If event attendees are to be included in marketing efforts, they should be introduced in very small, controlled batches, and only after the primary warming process is complete.

Key considerations

• Legal compliance: Marketers must ensure their practices align with email marketing regulations like GDPR and CAN-SPAM, which often require explicit consent for commercial emails.
• List hygiene: Regularly cleaning email lists is crucial, and unverified event attendees can quickly degrade list quality.
• Nurturing vs. marketing: Event attendees may be suitable for initial follow-up emails related to the event, but converting them into marketing subscribers requires a separate opt-in step.
• Avoid purchased lists: Marketers strongly advise against purchasing event attendee lists, as these typically lack the necessary consent and carry significant deliverability risks.
• Engagement measurement: Focus on metrics like open rates, click-through rates, and conversions from consented lists rather than simply increasing send volume with unverified contacts, as this affects overall deliverability.

Key opinions

• Universal caution: Experts universally recommend treating event attendee lists as highly risky for email warming unless there is 100% certainty of explicit consent for marketing.
• Reputation damage: Sending to unconsented lists invariably leads to higher complaint rates, which are extremely damaging to a sender's reputation, potentially causing emails to land in spam folders or be blocked entirely.
• Ramp-up integrity: The initial email ramp-up period is crucial for establishing trust with ISPs and should exclusively involve highly engaged, explicitly opted-in contacts to ensure a solid foundation.
• Post-warming introduction: Any less engaged or potentially risky segments, such as certain event attendee lists, should only be introduced into the sending stream after the warming phase is complete and a stable, positive sender reputation has been achieved.
• Minimal increments: When the decision is made to include riskier segments, experts advise doing so in extremely tiny, controlled increments to mitigate any adverse impacts on deliverability.

Key considerations

• Sender reputation first: The paramount goal during warming is to build and maintain a robust sender reputation. Compromising this with low-quality lists is counterproductive and can lead to emails going to the spam folder.
• Spam trap risk: Unconsented lists, especially those from third-party sources or older events, carry a significant risk of containing spam traps, which are highly detrimental to deliverability and can result in blacklisting.
• Feedback loop analysis: Regularly reviewing feedback loop data is critical to identify and address any increases in abuse complaints stemming from new segments.
• Engagement signals: Mailbox providers heavily weigh positive engagement (opens, clicks, replies) in their filtering decisions. Event attendees without explicit marketing opt-in may not provide these vital signals.
• Long-term strategy: Experts suggest that sacrificing short-term list size for long-term deliverability and sender reputation is always the better strategy.

Key findings

• Mandatory consent: Email marketing laws (e.g., CAN-SPAM, GDPR) require explicit and verifiable consent for sending commercial emails, which typically goes beyond simple event registration.
• Affirmative action: Official guidelines define explicit opt-in as a clear, affirmative action by the subscriber indicating their desire to receive emails, not just event updates.
• Sender reputation dependency: Major email providers' documentation consistently links good sender reputation directly to subscriber engagement and rigorous list hygiene practices.
• Prohibition of risky sources: Documentation often contains strong warnings against using purchased lists or those gathered without clear consent due to their high risk of deliverability issues, including spam traps.
• Warming best practices: Official email warming guides universally recommend commencing the process with the most engaged and clearly opted-in email segments to build a positive sending history.

Key considerations

• Legal implications: Marketers must understand the specific legal consent requirements in their target regions to avoid penalties and ensure compliance.
• ISP guidelines: Adhering to the specific best practices recommended by major internet service providers like Google and Outlook is crucial for inbox placement, as outlined in their sender requirements.
• Data collection audit: Regularly audit your event data collection methods to ensure that the consent obtained explicitly covers future marketing email communications.
• Engagement measurement: Documentation highlights that low engagement metrics or high complaint rates from a list segment are clear indicators of poor list quality and potential deliverability issues.
• Subscriber control: Allowing subscribers to easily manage their preferences, as championed by initiatives like Gmail's 'Manage subscriptions' feature, can help reduce complaints.