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The Engagement 4Cast
If you’ve ever poured your heart and resources into an email campaign only to watch donation numbers flatline, you’ve likely fallen victim to what we call the Email Delivery Mirage.
In my December 2025 webinar with email strategy expert, Mary Getz, we pulled back the curtain on what we call the “dark arts” of email. In 2025, the rules of the game shifted. It’s no longer about whether your Email Service Provider (ESP) says a message was “delivered,” it’s about Inbox Placement.
And if you aren’t landing in the primary inbox, you are effectively invisible.
Below are the critical email deliverability takeaways every digital professional, nonprofit marketer, and fundraising leader must understand to escape the spam folder and reclaim their sender reputation.
Missed the webinar? Watch the recording here!
Most marketers celebrate a 99% delivery rate. But in the world of modern email deliverability, “delivered” just means the receiving server didn’t bounce your message. It does not mean the user ever saw it.
In 2025, roughly 15–17% of marketing emails are reported as delivered but land directly in the spam folder or are “silently dropped” by providers like Google and Microsoft.
To truly understand your performance, you must track your Inbox Placement Rate (IPR). If your open rates are dipping despite a high delivery rate, you likely have an inbox placement problem, not a content problem.
We used to talk about email authentication as a “best practice.” Today, it is a requirement for entry. As of early 2025, major inboxes, including Google, Yahoo, Apple and Microsoft have aligned their standards. Bulk senders without authentication are now blocked by default.
For anyone sending emails to more than 5,000 recipients a day, a DMARC policy is no longer optional. Without it, your rejection rate could soar as high as 95%.
Accessibility isn’t just about being inclusive, it’s an inbox deliverability signal. Mary and I discussed a common pitfall: using font sizes that are too small.
We’ve found that Outlook can penalize senders who use fonts below 14 pixels. At 4Site Studios, we now recommend a minimum of 16px for all body copy. Why? Because providers equate poor readability and “messy” code with low-value spam.
We’ve moved away from hand-coding every email in favor of MJML (Mailjet Markup Language). It allows us to produce clean, responsive code that “compiles” correctly for the insanity of cross-browser sending, ensuring your buttons don’t fall apart when someone opens your email in a dark-mode Outlook mobile app.
Personalization and segmentation are two sides of the same coin, they must work together or they will work against you. Mary shared a great example of “personalization gone wrong”: the generic “Dear Friend” fallback.
If your email says, “Friend, your donation will change the world,” it feels like a form letter. But if you lack a name, a more creative fallback, like “Today, your donation will change the world,” feels natural. Modern filters are incredibly sensitive to user engagement; if your “personalization” feels robotic, your subscribers won’t open it, and your reputation will take a hit.
If a supporter has engaged with five “Save the Arctic” alerts, stop sending them generic appeals. Use Arctic imagery. When you listen to what your supporters are telling you through their actions, your engagement, as well as your placement, will skyrocket.
Consistency is the heartbeat of a healthy sender reputation. Many organizations fall into a “Slinky cadence,” months of silence followed by a frantic burst of emails during year-end fundraising.
Inbox providers use algorithms to determine if your mail is wanted. A sudden spike in volume after a long silence is a massive red flag. Maintaining a steady, predictable cadence tells the algorithms who you are and that your subscribers expect to hear from you.
Deliverability is a constant evolution. You can have the most compelling story in the world, but it’s worthless if it isn’t seen. Email deliverability is no longer a set-it-and-forget-it task. It’s an ongoing discipline that blends:
To help you navigate these technical hurdles, we’ve developed the Email Deliverability Playbook. It includes our comprehensive 30-question audit checklist that we use at 4Site Studios to help our clients build and maintain a “Primary Inbox” reputation.
Prefer to tackle this one step at a time? Our 4-week Email Deliverability Learning Series breaks the playbook into manageable weekly emails. Each includes practical guidance and a checklist you can apply immediately. Sign up below and get the first lesson next Monday.
Let’s stop chasing delivery rates and start winning the inbox.
4Site Studios is a talented troupe of web professionals who are passionate about creating tools to support digital marketers. We love to hear from our community! Reach out to us with your thoughts and questions. And don’t forget to subscribe below to get notified when we post new blogs – no spam, just content👍🏼