Summary
Comcast blocks emails due to spam-like characteristics, stemming from low engagement, high complaint rates, and poor sender reputation accumulated over time. Prevention involves ensuring recipients genuinely want your messages through improved acquisition (double opt-in, clear consent), relevant content (segmentation, avoiding spam triggers), list hygiene (removing unengaged users), and easy unsubscribing. Monitoring IP/domain reputation, warming up new IPs, authenticating emails (SPF, DKIM, DMARC), and using feedback loops are also crucial.
Key findings
- Gradual Decline: Blocking usually isn't sudden but the result of a slow build-up of negative signals.
- Engagement Matters: Low engagement directly contributes to a poor sender reputation.
- Consent is Key: Explicit consent minimizes complaints and improves deliverability.
- Authentication is Essential: SPF, DKIM, and DMARC are vital for establishing trust.
- Content Quality: Spammy content triggers filters and increases complaints.
- Reputation Impacts Deliverability: A poor IP/domain reputation directly leads to blocking.
Key considerations
- Improve Acquisition: Use double opt-in and be transparent about communication.
- Refine Content: Review content, design, and subject lines to avoid spam triggers.
- Segment Your List: Tailor content to increase relevance and engagement.
- Implement Authentication: Configure SPF, DKIM, and DMARC for your sending domains.
- Monitor Reputation: Use tools to track your sender reputation and blacklist status.
- Prioritize List Hygiene: Remove unengaged users regularly to improve deliverability.
- Provide Easy Unsubscribes: Make unsubscribing simple and honor requests promptly.
- Warm Up New IPs: Gradually increase sending volume on new IPs.
What email marketers say
12 marketer opinions
Comcast blocks emails primarily due to perceived spam-like characteristics. This often stems from low engagement, high complaint rates, and poor sender reputation. To prevent this, it's crucial to ensure recipients genuinely want your messages. This involves improving acquisition practices, content relevance, list hygiene (removing unengaged users), and honoring unsubscribe requests. Monitoring IP and domain reputation, warming up new IPs gradually, authenticating emails properly (SPF, DKIM, DMARC), segmenting lists for targeted content, and avoiding spam triggers in email content are also essential steps.
Key opinions
- Spam Complaints: High rates of spam complaints directly lead to blocking. Address the root causes of complaints.
- Low Engagement: Lack of engagement (opens, clicks) signals that recipients don't want the emails, negatively impacting reputation.
- Poor Reputation: A damaged IP/domain reputation makes it more likely for Comcast to block emails.
- Bad Content: Spam trigger words, excessive links, and poor design can flag emails as spam.
- List Hygiene: Sending to inactive or uninterested users harms deliverability.
Key considerations
- Acquisition: Improve how you acquire email addresses. Use double opt-in and be transparent about communications.
- Content Quality: Carefully review your email content, design, and subject lines to avoid spam filters.
- List Segmentation: Segment your audience and tailor content to increase relevance and engagement.
- Authentication: Implement SPF, DKIM, and DMARC to verify your identity to ISPs.
- Monitoring: Regularly monitor your IP/domain reputation using tools like Google Postmaster Tools and blacklist checkers.
- Unsubscribes: Make it easy for users to unsubscribe and immediately honor these requests.
Marketer view
Email marketer from Litmus explains that you should only email people who have explicitly given you permission to do so, and that you should respect their preferences. Don't hide subscription information, and make unsubscribing as easy as possible.
3 Feb 2022 - Litmus
Marketer view
Email marketer from Quora suggests implementing double opt-in for all new subscribers. This ensures that only genuinely interested users are added to your list, which reduces the chance of spam complaints and improves engagement.
16 Oct 2021 - Quora
What the experts say
6 expert opinions
Comcast's email blocking is often a result of a gradual decline in sender reputation, stemming from low engagement and increased spam complaints. The key to preventing this lies in only sending emails to those who genuinely want them. Active consent, clear unsubscribe options (ideally at the top of the email), and proper email authentication (SPF, DKIM, DMARC) are crucial. Additionally, avoiding spammy content, such as broken links or content resembling phishing attempts, is vital for maintaining a positive sender reputation and preventing blocks.
Key opinions
- Gradual Decline: Comcast blocking is rarely sudden, but a consequence of accumulated negative signals over time.
- User Engagement: Low user engagement contributes to a negative sender reputation.
- Consent is Key: Sending emails without explicit consent increases spam complaints and blocks.
- Authentication Matters: Proper email authentication (SPF, DKIM, DMARC) establishes trust and prevents spoofing.
- Spammy Content: Content that resembles spam or phishing attempts is a fast track to getting blocked.
Key considerations
- Active Recipient Management: Actively manage your recipient list, removing unengaged users and those who complain.
- Easy Unsubscribe: Make it easy for recipients to unsubscribe, preferably with a prominent link at the top of the email.
- Obtain Active Consent: Ensure you have clear and active consent from recipients before sending emails.
- Implement Authentication: Implement SPF, DKIM, and DMARC to authenticate your emails.
- Content Review: Thoroughly review your email content to ensure it is not spammy and avoid broken links or phishing-like characteristics.
Expert view
Expert from Email Geeks explains that sudden email blocking often isn't sudden at all, but the result of a gradual decline in email reputation due to users not engaging with emails and marking them as spam over time.
23 Feb 2024 - Email Geeks
Expert view
Expert from Word to the Wise, Laura Atkins, explains the best way to avoid blocks are to get email authentication (SPF, DKIM, and DMARC) working. These technologies prove you are who you say you are.
11 Jun 2022 - Word to the Wise
What the documentation says
4 technical articles
Comcast blocks emails exhibiting spam-like patterns, influenced by factors like spam content, high complaint rates, and poor sender reputation. To mitigate this, employing email authentication protocols such as SPF, DKIM, and DMARC is essential for verifying email legitimacy and fostering trust with ISPs. Monitoring domain and IP reputation using tools like Google Postmaster Tools, alongside establishing feedback loops with ISPs, enables proactive identification and resolution of deliverability issues by addressing spam complaints and refining sending practices.
Key findings
- Spam Patterns Trigger Blocks: Comcast blocks emails deemed to have spam-like characteristics based on content and sending behavior.
- Authentication is Crucial: SPF, DKIM, and DMARC are vital for proving your email's legitimacy and preventing spoofing.
- Reputation Matters: Maintaining a positive domain and IP reputation is key to avoiding blocks.
- Feedback Loops Are Important: Feedback loops enable you to respond to complaints and improve your sending practices.
Key considerations
- Content Review: Regularly audit email content to avoid spam triggers and ensure quality.
- Implement Authentication: Ensure SPF, DKIM, and DMARC are properly configured for your sending domains.
- Reputation Monitoring: Use tools like Google Postmaster Tools to monitor your sender reputation.
- Feedback Loop Setup: Establish feedback loops with ISPs to receive spam complaints and adjust your sending practices accordingly.
Technical article
Documentation from RFC standards highlights the need for feedback loops with ISPs like Comcast. These feedback loops alert the sender when recipients mark emails as spam, allowing for proactive removal of those recipients and improvements to sending practices.
19 Dec 2022 - RFC-Online
Technical article
Documentation from Google Postmaster Tools explains using their tools to monitor your domain and IP reputation with Gmail users. While not directly Comcast, a good reputation with Gmail often translates to better deliverability with other ISPs as well. Watch out for spam complaints and feedback loop reports.
2 Jul 2024 - Google
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