Are email spam trigger word lists still effective?

No, not in the way they are often presented. Modern spam filters use sophisticated algorithms that analyze sender reputation, engagement, and content in context, rather than relying on simple keyword blacklists.

What should I prioritize instead of avoiding spam trigger words?

Focus on building a strong sender reputation, ensuring proper email authentication (SPF, DKIM, DMARC), maintaining a clean and engaged email list, and sending relevant, valuable content. These factors have a much greater impact on inbox placement .

Can specific organizations still block emails based on keywords?

While major ISPs don't rely on simple keyword lists, some organizations (like schools or businesses) implement their own custom content filters. These internal filters can still block emails based on specific keywords they deem inappropriate. This is an organizational decision, not a global ISP rule.

What kind of content still raises red flags with spam filters?

Content that appears deceptive, uses excessive capitalization or exclamation points, or has poor formatting can still trigger filters. It's the overall pattern and intent that matters, not just the presence of a single spammy word .

Are spam trigger word lists still relevant for email deliverability? - Content - Email deliverability - Knowledge base

For years, email marketers have lived under the shadow of spam trigger word lists. These lists, often circulated without clear sources, suggest that certain words or phrases automatically send emails to the spam folder. I've encountered countless scenarios where a 10% drop in open rates, for example, is immediately blamed on these mythical words by email service providers (ESPs). This prompts a natural question: are spam trigger word lists still a relevant concern for email deliverability today?

The belief in absolute spam trigger words is a relic of an earlier era in email filtering. Back when rudimentary keyword-based filters were common, avoiding words like "free" or "Viagra" might have had a more direct impact. However, the landscape of spam filtering has evolved dramatically.

Modern inbox service providers (ISPs) like

Gmail,

Outlook, and

Yahoo employ sophisticated algorithms that analyze a multitude of factors, not just individual words. These systems assess the overall context, sender reputation, engagement metrics, and authentication protocols to determine an email's legitimacy.

So, while outdated spam word lists persist on many blogs, relying solely on them is akin to using a compass to navigate by GPS in today's email world. They offer a highly incomplete and often misleading picture.

The evolution of spam filtering

The focus of modern email deliverability has shifted significantly from explicit keyword matching. While content still plays a role, it's about the entire message's intent and legitimacy, not just a few flagged terms.

Spam filters now evaluate the email holistically, considering elements like sender reputation, engagement signals, and technical authentication. If an email comes from a reputable sender, is authenticated correctly with SPF, DKIM, and DMARC, and recipients consistently engage with it (open, click, reply), then the presence of a word like "free" is unlikely to be the sole factor that lands it in the spam folder.

In fact, many deliverability experts now dismiss the concept of isolated spam trigger words as a primary concern. The old lists, often compiled from outdated SpamAssassin rules or observations from a simpler internet era, don't reflect the current sophistication of anti-spam technologies. While SpamAssassin used to rely more heavily on keyword-based scoring, its relevance for modern inbox placement has significantly diminished. You can learn more about its current impact in our guide on SpamAssassin's relevance for modern deliverability.

Instead of obsessing over specific words, it's far more effective to focus on building a strong sender reputation and ensuring your emails meet expected standards of legitimacy and relevance. This includes managing your list, sending engaging content, and avoiding practices that lead to spam complaints or spam trap hits.

The nuance of content filtering

While single words have less impact than they once did, certain patterns and content characteristics can still signal spam to filters. These aren't about arbitrary word lists but rather about deceptive practices or content that mimics known spam campaigns.

For instance, excessive use of all caps, exclamation points, strange formatting, or deceptive subject lines that don't match the content are still red flags. It's about the overall presentation and authenticity of your message, not just the inclusion of a specific problematic word.

Consider the difference between a legitimate promotion using the word "free" in a clear, well-formatted email from a trusted sender versus a suspicious email with multiple instances of "free!!!" in all caps, unusual characters, and originating from a newly registered domain. The latter will likely be flagged, not because of the word "free" alone, but due to a combination of suspicious signals. This is why focusing on overall email content and sender behavior is critical.

Outdated focus: single words

Assumption: Avoiding specific keywords guarantees inbox delivery.
Method: Manually scanning content against static lists of hundreds of trigger words.
Effectiveness: Very low and prone to false positives, as legitimate emails can use common words.

For more on problematic patterns, you can refer to our article on what words and phrases are considered spammy.

Custom organizational filters

While major ISPs have moved past simple keyword blacklists (or blocklists), it's important to acknowledge that some organizations implement their own custom content filters. These are typically set up by IT administrators for specific internal domains (e.g., within a school, a government agency, or a large corporation) to block emails containing certain words or phrases that they deem inappropriate or risky for their users.

These custom filters often involve simple, static lists that can indeed flag emails based on specific keywords, regardless of the sender's overall reputation. For example, a school might block any email containing terms related to adult content or certain commercial offers. These lists are often copy-pasted from older, less sophisticated sources, and their logic can be quite rudimentary.

If you're experiencing deliverability issues to a very specific set of recipient domains, especially within niche industries or institutions, it's possible you're hitting one of these custom filters. Google provides guidance for administrators on how to add custom spam filters to Gmail, highlighting that such capabilities exist at an organizational level.

However, these are typically isolated cases and don't reflect the general approach of major ISPs. You can't change their internal policies, but understanding this possibility helps in diagnosing persistent deliverability problems to specific segments of your audience.

Prioritizing true deliverability factors

Given the shift in how spam filters operate, what should marketers and businesses focus on to ensure their emails reach the inbox? The answer lies in a multi-faceted approach that prioritizes legitimate sending practices over keyword avoidance.

First and foremost, establish and maintain a strong sender reputation. This is built over time through consistent positive engagement, low complaint rates, and adherence to email sending best practices. Your domain reputation is paramount.

Secondly, ensure your email authentication records (SPF, DKIM, and DMARC) are correctly configured. These protocols verify your sending identity and significantly reduce the likelihood of your emails being flagged as spoofed or fraudulent. A simple guide to DMARC, SPF, and DKIM can help you get started.

Lastly, focus on sending valuable, engaging content to a well-maintained and permission-based list. High engagement rates and low complaint rates are strong signals to ISPs that your emails are wanted. This holistic approach is far more impactful than meticulously avoiding outdated spam word lists.

Views from the trenches

Best practices

Maintain consistent sending volume and frequency to build a predictable sending reputation with ISPs.

Segment your email lists and tailor content to ensure relevance and increase recipient engagement.

Regularly clean your email lists to remove inactive subscribers and

spam traps

Common pitfalls

Blindly following outdated spam trigger word lists, leading to unnecessary content restrictions.

Focusing solely on content without addressing underlying sender reputation or technical authentication issues.

Purchasing or using old email lists that contain spam traps or unengaged recipients.

Ignoring low open rates or high bounce rates, which are key indicators of deliverability problems.

Expert tips

Monitor your deliverability metrics using

Google Postmaster Tools

and

other tools

Expert view

Expert from Email Geeks says if the content didn't change while switching ESPs, it's hard to blame the content. The new ESP should explain their reasoning. A 10% drop across all mail providers suggests it's not a deliverability issue but possibly related to open rate calculation or bot filtering.

2023-05-19 - Email Geeks

Expert view

Expert from Email Geeks says the advice to avoid words like "FREE" has been around for decades, originating from an era when spam filters were far less sophisticated.

2023-05-19 - Email Geeks

The path forward for deliverability

In conclusion, while the concept of rigid spam trigger word lists might feel intuitive, it's largely an outdated notion in the modern email ecosystem. Today's email deliverability is determined by a complex interplay of factors, with sender reputation, authentication, and user engagement at the forefront.

Chasing after ephemeral spam words from an unverified list distracts from the real work of building trust with ISPs and your audience. Focus on genuine value, consistent sending practices, and robust technical foundations. This holistic approach will serve your deliverability goals far better than any outdated blacklist.