Summary
The deliverability of emails, especially during warm-up phases, is a complex issue with varying perspectives on the impact of spam trigger words, PDF attachments, and links. While some experts argue that spam trigger words are largely outdated, others suggest they still have an impact, particularly aggressive or misleading language. There is a general consensus that maintaining a strong sender reputation through list hygiene, engagement, and authentication is paramount. Attaching PDFs, especially for new senders, is generally discouraged due to malware risks and filter sensitivities. As for links, focusing on wanted mail and linking to your website are recommended. A gradual warm-up strategy and continuous monitoring of deliverability metrics are essential.
Key findings
- Spam Trigger Words: Conflicting Views: Some argue spam trigger words are outdated, while others believe they still impact deliverability.
- Sender Reputation is Key: A strong sender reputation, built through list hygiene, engagement, and authentication, is crucial.
- PDFs Pose Risks: Attaching PDFs, particularly for new senders, can negatively impact deliverability due to malware concerns.
- Links: Quality and Relevance Matter: Focus on providing value; link to your website rather than external PDF downloads; consider external links during the warm up phase.
- Monitor and Test: Continuously monitor deliverability metrics and test emails for potential issues.
Key considerations
- List Hygiene: Maintain a clean email list and avoid spam traps.
- Authentication: Use SPF, DKIM, and DMARC to authenticate your emails.
- Content Quality: Create engaging and relevant content to improve engagement and avoid spam complaints.
- Gradual Warm-up: Implement a gradual warm-up strategy, starting with low volume to engaged users.
- Wanted Mail: Prioritize sending emails that recipients actually want to receive.
What email marketers say
10 marketer opinions
The impact of spam trigger words, PDF attachments, and links on email warm-up and deliverability is nuanced. While keyword filtering is largely outdated, modern spam filters prioritize sender reputation, engagement, and authentication. Focusing on building a clean email list, using double opt-in, sending relevant content, and warming up your domain gradually are crucial for establishing a positive sender reputation. Attaching PDFs can negatively impact deliverability, and links, especially to external sites, should be limited during the initial warm-up phase. Monitoring sender reputation, testing emails for spam triggers, and using personalized tracking links can further improve deliverability.
Key opinions
- Keyword Filtering: Keyword filtering is largely outdated, and modern spam filters focus on other factors.
- Sender Reputation: Building a positive sender reputation through list hygiene, engagement, and authentication is critical.
- PDF Attachments: Attaching PDFs can negatively impact deliverability, especially for new domains.
- Links: Limiting links, especially to external sites, during warm-up is advisable.
- Testing: Testing emails for spam triggers, rendering issues, and broken links is essential.
- Warm-up strategy: A new domain should spend 4-8 weeks warming up
Key considerations
- List Hygiene: Maintain a clean email list and focus on obtaining permission to avoid spam traps.
- Content Relevance: Send relevant and engaging content to avoid spam complaints.
- Authentication: Properly authenticate your emails using SPF, DKIM, and DMARC.
- Warm-up: Warm up your domain gradually to establish a positive reputation with ISPs.
- Link Personalization: Use personalized tracking links to demonstrate engagement.
Marketer view
Email marketer from ActiveCampaign mentions that sender reputation is a critical factor for email deliverability. Sending emails from a new domain or IP address requires a warm-up period to establish a positive reputation with ISPs. Sending high volumes of emails too quickly, especially to unengaged recipients, can negatively impact your reputation and lead to deliverability issues. They make no specific mention of pdfs or trigger words.
26 Jul 2021 - ActiveCampaign
Marketer view
Email marketer from Reddit shares a warm-up strategy, starting with low volume to engaged users, then slowly increasing volume. Suggests avoiding attachments and focusing on valuable content initially. They stated a new domain should spend 4-8 weeks warming up. They did not mention spam words.
13 Mar 2025 - Reddit
What the experts say
7 expert opinions
The impact of spam trigger words, PDF attachments, and links on email deliverability is complex and somewhat contradictory. While some experts believe that spam trigger words are largely outdated and that sender reputation and engagement are more important, others suggest that certain words and phrases can still negatively impact deliverability. There's a consensus that attaching PDFs, especially for new senders, is risky due to malware concerns and filter sensitivities. Regarding links, focusing on delivering wanted mail is key, and linking to your website is generally preferred over linking to PDFs on Google Drive.
Key opinions
- Spam Trigger Words: Conflicting views exist: some say trigger words are outdated, others say they still have an impact.
- Sender Reputation: Building a healthy sender reputation is crucial for deliverability.
- PDF Attachments: Attaching PDFs, especially for new senders, is generally discouraged due to malware risks.
- Links: Focus on delivering wanted mail; link to your website rather than external PDF downloads.
Key considerations
- Wanted Mail: Prioritize sending emails that recipients actually want to receive.
- Risk Mitigation: Avoid practices that raise red flags for spam filters (e.g., PDF attachments from new senders).
- Context Matters: Consider that filters are complex and constantly changing, and content is only one factor.
Expert view
Expert from Email Geeks says that a styled link to a PDF on Google Drive would make them nervous, and recommends linking to your website instead.
21 Jul 2022 - Email Geeks
Expert view
Expert from Word to the Wise explains that focusing on delivering wanted mail is key. They also highlight that what might be considered as "free" for the recipient comes at a cost for the sender. They suggest moving on from thinking just about the word "free" and to focus on sending wanted mail.
3 Feb 2022 - Word to the Wise
What the documentation says
4 technical articles
Email deliverability, according to these documentation sources, depends on a multifaceted approach involving sender reputation, authentication, content quality, and list hygiene. Avoiding spam triggers and deceptive practices, ensuring proper authentication (SPF, DKIM, DMARC), and providing clear unsubscribe options are crucial. While PDF attachments aren't inherently bad, large file sizes and poor sender reputation can trigger spam filters. Linking to content on your website is generally preferred. URL shorteners can also sometimes trigger spam filters. Monitoring bounce rates and spam complaints is essential for maintaining good deliverability.
Key findings
- Multifaceted Approach: Email deliverability depends on a combination of factors, not just one element.
- Sender Reputation: A positive sender reputation is crucial for getting emails delivered.
- Authentication: Proper authentication (SPF, DKIM, DMARC) is essential for verifying your identity.
- Content Quality: High-quality content that avoids spam triggers is important.
- List Hygiene: Maintaining a clean and engaged email list is necessary.
- PDF Attachments: While not inherently bad, large PDF attachments can negatively impact deliverability.
- URL Shorteners: Using URL shorteners can sometimes trigger spam filters.
Key considerations
- Spam Triggers: Avoid practices that are commonly associated with spam.
- Responsible Practices: Adhere to responsible email marketing practices.
- Monitoring: Continuously monitor bounce rates, spam complaints, and other metrics to identify and address deliverability issues.
- Website Links: When possible, link directly to the website rather than PDFs.
Technical article
Documentation from SparkPost advises focusing on sender authentication, list hygiene, and content quality to improve deliverability. They note that using URL shorteners can sometimes trigger spam filters and that monitoring bounce rates and spam complaints is essential.
23 Oct 2024 - SparkPost
Technical article
Documentation from Mailchimp states while PDF attachments themselves aren't inherently bad, they can increase the size of your emails and potentially trigger spam filters if they're unusually large or if your sending reputation is poor. Linking to content hosted on your website is generally recommended.
9 Jul 2021 - Mailchimp
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