Summary
Email marketing presents several surprising truths. CAN-SPAM doesn't require opt-in, yet good practice emphasizes permission. Using "FREE!!!" is permissible, but judiciously. Engagement metrics significantly influence sender reputation beyond just spam complaints, and even smaller blocklists can have an outsized impact. Deliverability extends beyond inbox/spam, with tab placement critical. Smaller, engaged lists often beat larger, unengaged ones, and plain text can sometimes trump HTML. Segmentation, personalization, and A/B testing are essential, while excessive frequency harms engagement. Accurate email rendering, streamlined unsubscribes, and proper technical configurations (header length, SPF) are crucial for optimal performance.
Key findings
- CAN-SPAM Nuance: CAN-SPAM doesn't mandate opt-in, although best practice focuses on permission.
- Subject Line Tactics: Using 'FREE!!!' in subject lines is permissible but needs careful consideration.
- Holistic Reputation: Sender reputation is greatly determined by engagement metrics (opens, clicks, deletes).
- Small Blocklist Impact: Smaller, lesser-known blocklists can have unexpectedly large impact.
- Deliverability Depth: Deliverability is more than just inbox vs. spam; tab placement affects visibility.
- Quality Over Quantity: Smaller, engaged lists yield more than large, unengaged lists.
- Plain Text Power: Plain text emails sometimes beat HTML for deliverability and engagement.
- Personalization Boost: Personalization and segmentation significantly lift engagement and performance.
- Frequency Balance: Excessive email frequency harms engagement and increases unsubscribes.
- Rendering Importance: Emails render differently across platforms; testing is crucial.
- Unsubscribe Ease: Difficult unsubscribing harms reputation; make it simple.
- Technical Limits: Exceeding header length limits causes delivery issues.
- SPF Records: Misconfigured SPF records can flag legitimate emails as spam.
Key considerations
- Ethical Compliance: Prioritize ethical opt-in practices over bare CAN-SPAM compliance.
- Brand Voice: Use 'FREE!!!' and similar tactics only if it aligns with your brand.
- Engagement Focus: Actively monitor and improve engagement metrics for good sender reputation.
- Blocklist Vigilance: Monitor both large and small blocklists and address any listings promptly.
- Tab Optimization: Optimize emails to avoid the Gmail Promotions tab where possible.
- List Management: Focus on building an engaged list, not just a large one.
- Format Testing: Test both plain text and HTML formats to find the best option for your audience.
- Personalized Approach: Implement personalization and segmentation strategies.
- Frequency Cadence: Determine optimal email sending frequency to keep users engaged without overwhelming them.
- Cross-Platform Test: Test email rendering across various platforms.
- Streamlined Unsubscribe: Ensure easy unsubscribing to prevent spam complaints.
- Technical Compliance: Comply with email header length limitations to avoid delivery issues.
- SPF Configuration: Correctly configure SPF records.
What email marketers say
10 marketer opinions
Several surprising truths about email marketing have been identified. CAN-SPAM doesn't require opt-in, and Gmail tab placement can be worse than the spam folder. Smaller, engaged lists can outperform larger, unengaged ones, and plain-text emails can be effective. Segmentation and personalization are key for engagement, while excessive email frequency can harm your list. A/B testing and optimized unsubscribe processes help improve campaign performance and maintain sender reputation. Rendering across clients and devices matters.
Key opinions
- CAN-SPAM: CAN-SPAM Act doesn't mandate opt-in, a detail often misunderstood.
- Gmail Tabs: Placement in Gmail tabs can significantly impact visibility, sometimes more than the spam folder.
- List Size vs. Engagement: A smaller, engaged email list can be more valuable than a large, unengaged list.
- Plain Text Emails: Plain-text emails can sometimes outperform HTML emails in deliverability and engagement.
- Segmentation and Personalization: Segmenting your email list and personalizing emails improve engagement and performance.
- Email Frequency: Excessive email frequency can lead to unsubscribes and decreased engagement.
- A/B Testing: A/B testing email elements can provide valuable insights for optimization.
- Unsubscribe Process: Making unsubscribing difficult can backfire, potentially harming your sender reputation.
- Rendering: Emails often render differently across clients, necessitating testing on different platforms.
Key considerations
- Compliance: Understanding the nuances of CAN-SPAM is critical for legal compliance.
- Engagement Over Size: Focus on building an engaged list rather than just increasing list size.
- Testing and Optimization: Regularly A/B test your emails to identify what resonates with your audience.
- User Experience: Ensure a smooth unsubscribe process to avoid being marked as spam.
- Cross-Platform Compatibility: Test email rendering across different email clients and devices to ensure consistency.
- Balance Frequency: Find an email frequency that keeps subscribers engaged without overwhelming them.
- Personalization: Personalize email content to increase open rates and click-through rates.
- Segmentation: Segment your email list to deliver targeted content to different audience groups.
- Gmail Tabs: Optimize emails to avoid being placed in the Gmail Promotions tab, if possible.
Marketer view
Email marketer from Email on Acid shares that emails often render differently across various email clients and devices. It’s crucial to test your email design on different platforms to ensure a consistent experience for subscribers.
14 Aug 2024 - Email on Acid
Marketer view
Email marketer from Neil Patel's Blog explains that a smaller, highly engaged email list is often more valuable than a large, unengaged list.
18 Apr 2025 - Neil Patel's Blog
What the experts say
4 expert opinions
Several surprising truths regarding email marketing have been identified. Contrary to common assumptions, using "FREE!!!" in subject lines is permissible. Sender reputation is influenced by engagement metrics, not just spam complaints. Being on a smaller, lesser-known blocklist can have a significant impact. Deliverability is more complex than inbox vs. spam folder, as tab placement also matters.
Key opinions
- Subject Line Freedom: Using 'FREE!!!' in subject lines is not inherently detrimental.
- Holistic Reputation: Sender reputation is heavily influenced by engagement metrics (opens, clicks, deletes).
- Small Blocklist Impact: Smaller, lesser-known blocklists can be surprisingly impactful.
- Deliverability Nuances: Deliverability extends beyond inbox/spam, with tab placement being a key factor.
Key considerations
- Subject Line Judgement: While 'FREE!!!' is permissible, consider your brand and target audience before using such tactics.
- Monitor Engagement: Actively monitor engagement metrics to gauge and improve sender reputation.
- Blocklist Awareness: Be aware of both major and minor blocklists and take steps to avoid being listed.
- Tab Placement Strategy: Optimize email content and sending practices to influence tab placement (e.g., avoid the Gmail Promotions tab).
Expert view
Expert from Email Geeks says that you can use FREE!!! in the subject line.
12 Oct 2021 - Email Geeks
Expert view
Expert from Spamresource shares that being on a smaller, lesser-known blocklist can sometimes have a greater impact than being on a major one, as smaller blocklists are often used as key indicators by specific organizations or spam filters.
26 Dec 2023 - Spamresource
What the documentation says
4 technical articles
Email marketing has several technical aspects critical to deliverability. Email header fields have length limits that, if exceeded, cause delivery problems. Sender reputation is a major factor influencing deliverability, assessed by Google and others. High bounce rates negatively impact sender reputation and can lead to blocking. Properly configuring SPF records is essential; misconfiguration can flag legitimate emails as spam.
Key findings
- Header Limits: Email header fields have length restrictions; exceeding these can cause delivery issues.
- Sender Reputation: Sender reputation is a critical factor for email deliverability, assessed by ISPs like Google.
- Bounce Rates: High bounce rates negatively impact sender reputation and can lead to blocking.
- SPF Configuration: Properly configured SPF records are essential; misconfiguration can flag legitimate emails as spam.
Key considerations
- Header Compliance: Ensure email header fields comply with RFC 5322 length limitations to avoid delivery problems.
- Reputation Management: Proactively manage sender reputation by monitoring deliverability metrics and adhering to best practices.
- List Hygiene: Maintain a clean email list to minimize bounce rates and protect sender reputation.
- Authentication: Implement SPF and other email authentication methods to improve deliverability and prevent spoofing.
Technical article
Documentation from IETF RFC 3501 details the complexities of SPF records. It's not simply a matter of adding a record; misconfiguration can lead to legitimate emails being flagged as spam. Proper syntax and understanding of SPF mechanisms are essential.
7 Dec 2024 - RFC 3501
Technical article
Documentation from Google Postmaster Tools highlights that sender reputation is a critical factor in email deliverability. Google uses various signals to assess sender reputation, and a poor reputation can lead to emails being filtered into the spam folder or blocked altogether.
3 Feb 2023 - Google Postmaster Tools
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