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Email deliverability has quietly shifted from a purely technical discipline to a behavioral one. SPF, DKIM, and clean IPs still matter, but inbox placement is increasingly determined by how subscribers respond to your emails.
Mailbox providers — Gmail, Outlook, Yahoo — now evaluate engagement signals the same way social platforms evaluate user behavior: if your audience interacts, you’re rewarded with reach. If they ignore you, your sender reputation drops.
For GTM teams dependent on outbound motion, this is a critical shift. A well-structured offer won’t matter if the email never makes it to the inbox.
This edition breaks down why engagement plays such a powerful role in deliverability — and how to engineer it.
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Why Engagement Is Now a Ranking Signal
Mailbox providers have a simple objective: deliver valuable messages and filter out noise.
To decide which is which, they look at:
Positive signals: opens, clicks, replies, forwarding, adding to contacts
Negative signals: spam complaints, deletions without reading, ignoring emails consistently, marking as junk
When positive behaviors outweigh negative ones, your sender score rises, and more of your emails land in the primary inbox instead of promotions or spam.
Put simply:
If people engage, your emails get delivered. If they don’t, your future emails get downgraded.
The Engagement-Deliverability Flywheel
High engagement → Better deliverability → Higher inbox placement → More engagement → Stronger sender score.
This creates a compounding effect.
But the reverse is also true: poor engagement accelerates your decline.
Understanding this flywheel helps GTM teams shape their outbound and lifecycle strategy with more precision.
How Mailbox Providers Track Engagement
While algorithms are opaque, consistent patterns have emerged:
1. Opens and Clicks
Basic but essential. Even with privacy changes, aggregate behavior still influences reputation.
2. Replies
A reply is the strongest possible signal. It communicates that the sender is human, relevant, and trusted.
3. Time Spent Viewing Email
Quick deletion vs. reading time signals whether the content was worth opening.
4. Deleting Without Opening
This is one of the fastest routes to spam-folder purgatory.
5. Spam Complaints
Even a tiny complaint rate (0.1–0.3%) can tank your domain reputation for weeks.
6. Engagement History
Mailbox providers consider how each subscriber has interacted with you over time.
If your list includes thousands of dormant subscribers, they pull down your entire domain.
How GTM Teams Can Increase Engagement (Ethically, Consistently)
1. Tighten Your Targeting
List expansion isn’t always progress.
Lists should be built, not bought.
The tighter the fit, the higher the engagement.
Segment relentlessly by:
Industry
Buying stage
Prior interaction
Org size
Pain point
Relevance is the most consistent driver of engagement.
2. Use Personalisation That Actually Matters
Not [first_name], but:
Relevant POV
Contextual insights
Industry-tailored outcomes
Trigger-based messaging tied to events or activity
The more your message mirrors your prospect’s reality, the higher the interaction rate.
3. Clean Your List Proactively
Remove or suppress inactive subscribers regularly.
For cold email:
Drop leads who haven’t opened any message after 5–6 touches.
For warm email:
Build re-engagement flows, then sunset non-responders.
Fewer unengaged subscribers = higher sender reputation.
4. Encourage Replies Everywhere
Replies are algorithmic gold.
Ask questions like:
“Is this a priority for you right now?”
“Worth exploring further?”
“Did I completely miss the mark?”
An uninterested reply is better than no reply.
5. Warm Up Your Domain — Always
Domain warming isn't just for cold email blasts.
Any new domain or sending increase should start with warmed, engaged audiences to build early positive signals.
A warmed domain + engaged list = inbox placement stability.
6. Optimize Send Cadence for Human Behavior
Consistency > frequency.
Irregular sending patterns signal spam-like behavior.
Align cadence to:
audience expectations
content value
time zones
Where possible, use engagement-based sending.
Send more to high-engagers, less to low-engagers.
A Framework for Sustainable Engagement
To keep your sender score healthy over months, follow this simple pattern:
Start with a clean, segmented, relevant list.
Send high-context messages, not templates.
Monitor engagement and prune aggressively.
Ask for replies early and often.
Automate warming and reputation monitoring.
Behavior shapes deliverability.
Deliverability shapes reach.
Reach shapes revenue.
Final Thoughts
Email isn’t just a channel — it’s an algorithmic ecosystem. And the teams that master deliverability through engagement aren’t just getting higher open rates; they’re securing a structural advantage.
As inbox competition intensifies, engagement becomes the new currency of deliverability. The more your audience interacts, the more your emails become impossible for algorithms to ignore.
See you next time,
— Team GTM Society