How are email receivers pressured to allow more mail?
Michael Ko
Co-founder & CEO, Suped
Published 22 May 2025
Updated 15 Aug 2025
7 min read
Email receivers, like Gmail or Yahoo, stand at a critical intersection in the email ecosystem. Their primary role is to protect users from unwanted mail, often referred to as spam, while ensuring legitimate messages reach the inbox. This balancing act is far more complex than it appears, as they face constant pressure from multiple directions to adjust their filtering policies and allow more mail.
The challenge stems from the sheer volume and diverse nature of incoming email. Every day, billions of messages traverse the internet, a significant portion of which is malicious or unsolicited. To manage this deluge, receivers employ sophisticated algorithms and various filters, including IP and domain reputation, content analysis, and user feedback. These systems are designed to be stringent by default to maintain inbox integrity, but this strictness often leads to legitimate mail being mistakenly filtered.
This inherent conflict sets the stage for continuous negotiation. On one side are the senders, who want their messages to reach recipients without fail. On the other side are the receivers, whose priority is the user experience. Bridging this gap requires an understanding of the pressures these receivers face and the mechanisms they use to mitigate them, all while trying to satisfy conflicting demands.
The dual challenge of email filtering
The core dilemma for any email receiver is the distinction between desired and undesired mail. They aim to deliver all the emails their users want and keep out all the ones they do not want. This mission statement sounds simple, but its execution is incredibly complex given the constantly evolving tactics of spammers and the legitimate needs of senders.
Mailbox providers often operate with the assumption that if an email is not actively engaged with (opened, clicked), it is less likely to be wanted. This leads to filtering decisions that can impact legitimate bulk senders. They balance the need to protect users from overwhelming amounts of unwanted email with the desire to facilitate useful communication. This often leads to weird filtering decisions from a sender's perspective, but are rooted in safeguarding the user's inbox experience.
Sender's perspective
Maximizing reach: Senders want their messages to reach every intended recipient, viewing each blocked email as a lost opportunity.
Campaign performance: High bounce rates or low inbox placement directly impact marketing and communication metrics.
Receiver's perspective
User protection: Safeguarding users from spam, phishing, and unwanted bulk mail is paramount.
Maintaining service quality: An inbox flooded with junk mail leads to user dissatisfaction and churn.
This fundamental difference in objectives means that email receivers are always under pressure. They must balance the desire for frictionless email delivery with the absolute necessity of preventing abuse and maintaining a clean inbox experience for their users.
Internal and external pressures on receivers
Email receivers face pressure from several stakeholders. Internally, their own marketing and sales teams often push for maximum deliverability, sometimes without fully understanding the technical complexities or reputation implications. There's an expectation that every email sent should reach the inbox, even when sending practices might not align with industry best practices. This internal pressure can lead to difficult conversations for postmasters and deliverability teams who must uphold strict filtering standards while supporting internal business goals.
Externally, senders constantly advocate for their legitimate mail to be delivered. This includes large ESPs, transactional email providers, and direct marketers. When legitimate mail is blocked or sent to spam folders, senders often contact the receiver's postmaster or support teams, demanding explanations and changes. These complaints, while sometimes justified, add to the pressure on receivers to fine-tune their filters and potentially whitelist certain IPs or domains.
Adding to this, there's pressure from the users themselves. While users hate spam, they also get frustrated when important emails, such as password resets, order confirmations, or newsletters they signed up for, don't arrive. This can lead to support tickets and negative feedback directed at the mailbox provider. Research suggests that recipients often overestimate the urgency of emails, leading to heightened frustration when mail is delayed or blocked.
New sender requirements
Major players like Gmail and Yahoo have recently updated their sender guidelines, requiring bulk senders to implement stronger authentication and maintain low spam rates. These changes, while aimed at improving user experience, also put pressure on receivers to correctly identify compliant senders versus spammers. You can learn more about how they are enforcing these new requirements.
Balancing act and policy adjustments
Given these pressures, email receivers are constantly refining their filtering strategies. They understand that overly aggressive filtering leads to user complaints about missing important mail, while overly lenient filtering leads to spam-filled inboxes. This creates a delicate balance, pushing them to use a multi-layered approach to email security and deliverability. Factors such as domain reputation, sender IP reputation, content analysis, and user engagement metrics are all continuously weighed.
To allow more legitimate mail while maintaining security, receivers often implement email throttling or deferrals for new or less reputable senders. This allows them to observe sender behavior over time, gradually increasing sending limits if the mail stream proves to be clean and engaging. It's a risk-averse approach that prioritizes user safety while providing a pathway for legitimate senders to establish trust.
Receivers also rely heavily on blocklists (or blacklists) and internal reputation scores to make filtering decisions. However, they understand that a blanket blocklist can inadvertently affect legitimate senders sharing an IP or domain. This pushes them to develop more granular, real-time filtering that considers multiple signals rather than relying solely on a single factor. User complaints and engagement signals are paramount in these systems, as they represent direct feedback from the inbox owner.
Ultimately, receivers are pressured to find a middle ground where they can protect their users without overly restricting legitimate communication. This involves continuous monitoring, analysis of email traffic patterns, and adapting their filtering logic to stay ahead of new threats and accommodate evolving sending practices.
The role of authentication and reputation
For senders, understanding the pressure on receivers highlights the critical importance of email authentication and sender reputation. Mechanisms like SPF, DKIM, and DMARC provide receivers with cryptographic assurances that an email genuinely originates from the stated sender and has not been tampered with. These are fundamental building blocks for establishing trust and overcoming initial filtering hurdles.
Here's an example of a simple DMARC record that helps receivers verify your mail:
Beyond authentication, maintaining a positive sender reputation is paramount. This means consistently sending wanted mail to engaged recipients, avoiding spam traps, and minimizing spam complaints. Receivers actively monitor user interaction and feedback, and this data directly influences their willingness to accept your mail. A strong reputation can pressure receivers to be more lenient, knowing that the sender is trustworthy. Conversely, a poor reputation will lead to stricter filtering, higher bounce rates, and potentially even getting listed on a blocklist or blacklist.
Best practices for senders
Authenticate email: Implement SPF, DKIM, and DMARC for all sending domains.
Maintain list hygiene: Regularly clean your email lists to remove inactive or invalid addresses.
Monitor engagement: Pay attention to open rates, click-through rates, and unsubscribe rates. These are key reputation signals.
Provide easy unsubscribe: Make it simple for recipients to opt out of your mailing lists.
Views from the trenches
Best practices
Actively monitor spam complaint rates and user engagement metrics across all mailbox providers.
Ensure all sending domains are properly authenticated with SPF, DKIM, and DMARC records.
Implement a clear and easy unsubscribe process for all marketing and bulk emails.
Segment your audience and send relevant content to improve engagement and reduce complaints.
Common pitfalls
Ignoring feedback loops from mailbox providers, which indicate spam complaints.
Sending to unengaged lists, leading to high bounce rates and low open rates.
Not implementing DMARC or having misconfigured SPF/DKIM records.
Failing to adapt sending practices to new industry guidelines and requirements.
Expert tips
Invest time in understanding the specific filtering nuances of major mailbox providers.
Proactively engage with postmaster teams when issues arise, providing detailed information.
Educate internal marketing teams on the importance of deliverability best practices.
Leverage DMARC reports to identify authentication failures and potential abuse of your domain.
Expert view
Expert from Email Geeks says the conflicting feedback from 'spammers suck' and 'ISPs suck' comments highlights the fundamental disagreement between senders and receivers about email filtering.
2020-04-09 - Email Geeks
Expert view
Expert from Email Geeks says a significant divide exists between senders and receivers, suggesting that achieving empathy and bridging this gap is crucial for better email deliverability.
2020-04-09 - Email Geeks
Navigating the email deliverability landscape
Email receivers are constantly under pressure to strike a balance between user protection and accommodating legitimate senders. This dynamic environment requires them to continuously evolve their filtering mechanisms, leaning on advanced authentication, sender reputation, and user feedback to inform their decisions. For senders, this means that success hinges on more than just sending volume; it depends on the quality of their mailing lists, the relevance of their content, and strict adherence to established best practices.
By understanding the pressures faced by email receivers, senders can better align their strategies to ensure their messages consistently reach the inbox. Focusing on proper authentication, maintaining a clean sending reputation, and prioritizing user engagement are key to navigating the complex landscape of email deliverability.
Yahoo, stand at a critical intersection in the email ecosystem. Their primary role is to protect users from unwanted mail, often referred to as spam, while ensuring legitimate messages reach the inbox. This balancing act is far more complex than it appears, as they face constant pressure from multiple directions to adjust their filtering policies and allow more mail.
Gmail and Yahoo have recently updated their sender guidelines, requiring bulk senders to implement stronger authentication and maintain low spam rates. These changes, while aimed at improving user experience, also put pressure on receivers to correctly identify compliant senders versus spammers. You can learn more about how they are enforcing these new requirements.
