How can I intentionally deliver emails to the spam folder?

Key findings

• Content flags: Using common spam phrases (e.g., Nigerian prince), misleading subject lines like 'Re:' or 'Fwd:', excessive capitalization, and hidden text are surefire ways to trip spam filters.
• Reputation damage: Sending from an IP address with no warm-up, or from domains previously associated with spam, will quickly degrade your sender reputation, making it easier to land in the spam folder.
• Authentication failures: Failing to implement or deliberately misconfiguring authentication protocols like SPF, DKIM, and DMARC signals to mail servers that your emails are suspicious.
• Blacklisted elements: Including URLs or even images from domains that are known to be on an email blacklist or blocklist can instantly trigger spam filters. This includes using a GTUBE string.
• Recipient behavior: Sending to unengaged lists, scraped email addresses, or spam traps will lead to high complaint rates and low engagement, signaling spam.

Key considerations

• Account suspension risk: Email service providers (ESPs) actively monitor for spamming behavior. Intentionally sending spam will likely lead to your account being flagged and potentially shut down, even if your stated intent is unusual.
• Shared IP impact: If you are using a shared IP, your actions could negatively affect other senders using the same IP, leading to broader deliverability problems for unrelated parties.
• Blocking vs. spam folder: While the goal is the spam folder, persistent spammy behavior often escalates to outright blocking, meaning emails won't even reach the spam folder but will be rejected entirely. Yahoo, for example, has a clear escalation policy.
• Ethical implications: Deliberately causing email to be marked as spam, even for a non-malicious purpose, still contributes to the overall noise in the email ecosystem and can be viewed as an abuse of email infrastructure.

Key opinions

• Abusive content: Many suggest that including stereotypical scam language, such as mentions of Nigerian princes or large sums of money, is a highly effective way to trigger spam filters. Marketers note that masking emails with 'Re:' or 'Fwd:' in the subject line can also trick filters.
• IP and domain reputation: Sending from an IP that hasn't been properly warmed up, or from providers known for less stringent email policies, is cited as a method to achieve poor deliverability and land in spam.
• Blacklisted elements: Including a URL that is already on a Spamhaus domain blocklist or using the EICAR-STANDARD-ANTIVIRUS-TEST-FILE string in the subject can almost guarantee spam placement.
• List quality: Marketers recognize that sending to scraped email addresses or non-opt-in lists will lead to high spam complaints, which is a significant factor in being flagged.

Key considerations

• Provider policies: Even for unique projects, email providers (like Substack) may not fully comprehend an intent to send spam and could still flag or shut down accounts to maintain their platform's reputation. It's important to understand why emails go to spam in general, and then do the opposite.
• Deliverability management: Maintaining a sender's ability to even reach the spam folder consistently can be a challenge. The line between landing in spam and being outright rejected is very fine.
• Unpredictable outcomes: The methods that cause emails to land in spam are often unpredictable and can lead to emails being blocked entirely, rather than just filtered. This is why determining if emails are going to spam can be tricky even for legitimate senders.
• Broader impact: Deliberately engaging in spam-like activities can negatively affect the reputation of shared email infrastructure, potentially causing issues for other users.

Key opinions

• Sophisticated filtering: Experts affirm that modern spam filters, particularly those used by major providers like Google and Microsoft, employ highly sophisticated algorithms that analyze numerous factors beyond simple keywords to identify and classify spam.
• Reputation is paramount: A sender's reputation (both IP and domain) is the most critical factor. Deliberately harming this reputation, for example, by sending from an entirely new, unwarmed IP, is a primary way to trigger spam classification.
• Blacklist effectiveness: Inclusion on major blacklists (also known as blocklists), such as Spamhaus, is almost a guarantee of emails being diverted to spam or rejected. Experts suggest using URLs from blacklisted domains as a potent trigger.
• Escalation policies: Mailbox providers like Yahoo have explicit escalation policies where repeated spam-like behavior leads from spam folder placement to increasingly severe blocks, ultimately resulting in outright rejection. This is a key reason why emails go to spam for legitimate senders.

Key considerations

• Unintended consequences: While aiming for spam, senders risk being entirely blocked, making it impossible to deliver messages even to the spam folder. This is an outcome mailers often try to avoid, by understanding why emails land in spam.
• Infrastructure damage: Using a shared IP from a cheap virtual machine provider to send undesirable email can damage the reputation of that provider's IP space, affecting other legitimate users.
• Reliability of spam delivery: It's difficult to ensure consistent spam folder delivery without eventually being outright blocked. The goal of avoiding spam traps highlights the unpredictability of deliverability when engaging in negative practices.

Key findings

• Authentication issues: Documentation consistently highlights that failing DMARC verification, or misconfiguring SPF and DKIM records, is a primary reason for emails being marked as spam or rejected.
• Content analysis: Technical documentation often details how spam filters analyze email content for suspicious patterns, including specific phrases, hidden text, and attempts to mimic phishing. The GTUBE string is a well-known example designed to trigger spam filters as per SpamAssassin documentation.
• Sender reputation: Official guidelines emphasize that poor sender reputation, stemming from high bounce rates, spam complaints, or sending to invalid addresses, is a critical factor leading to spam placement.
• List hygiene: Documentation frequently warns against sending to purchased or unverified email lists, as they often contain spam traps that instantly flag senders as spammers. Conversely, intentionally doing this will generate spam.

Key considerations

• Compliance reversal: To intentionally deliver to spam, one must actively disregard common compliance requirements like including clear unsubscribe links, which are vital for legitimate email marketing.
• Mimicking malicious activity: Deliberately using techniques like hiding content or sending from suspicious IP ranges can cause email systems to perceive the sender as malicious, potentially leading to more severe actions than just spam folder placement, such as an email blacklist entry.
• Algorithmic detection: Documentation from major email providers reveals they use sophisticated algorithms to differentiate legitimate emails from potential spam. These systems are constantly evolving to detect new spamming tactics.