Last month, a B2B software company sent 10,000 emails to a purchased list. Their sales VP called it “aggressive outreach.” The FTC calls it a potential $510 million violation under CAN-SPAM – the US federal law governing commercial email that allows penalties up to $51,744 per non-compliant email in 2025. They didn’t know. Most don’t.
The line between email marketing and spam isn’t philosophical – it’s mathematical, legal, and increasingly enforced. Yet I watch companies cross it daily, convinced that volume compensates for strategy. It doesn’t. It accelerates the destruction of your sender reputation, and once that’s gone, your legitimate emails stop reaching anyone.
Why Emails Go to Spam – When Open Rates Become Vanity Metrics
Average email open rates across industries hover around 24% in 2025, with B2B averaging closer to 40%. Marketing teams obsess over these numbers, running A/B tests on subject lines, sending at optimal times, segmenting by behaviour. Valid tactics, all of them. But here’s what almost nobody tracks: complaint rates.
A complaint rate above 0.1% triggers deliverability problems with major email service providers. Research consistently shows that approximately 20% of deliverability issues stem directly from spam complaints. Yet most companies don’t monitor this metric until their emails stop reaching inboxes entirely.
By then, the damage compounds – lower delivery rates mean you send more emails to compensate, which generates more complaints, which further destroys deliverability. It’s a death spiral disguised as “aggressive marketing.”
I consulted with a B2C e-commerce brand sending daily promotional emails. Open rates looked healthy at 22%. Complaint rate was 0.3% – triple the threshold. Their emails were increasingly landing in spam folders, so they increased frequency to maintain revenue. Within three months, their primary domain was effectively blacklisted by major ISPs. Fixing it required migrating to a new domain and rebuilding sender reputation from zero. The cost: six months of reduced email revenue and €80,000 in remediation.
Compliance Is the Floor, Not the Ceiling
Here’s where it gets interesting: you can be fully compliant with CAN-SPAM and GDPR while still destroying your brand through spam behaviour.
GDPR requires explicit consent before sending marketing emails in the EU. CAN-SPAM requires accurate header information, clear unsubscribe options, and honouring opt-out requests within 10 business days. These are table stakes. They don’t address the strategic question: should you send this email just because you legally can?
A B2B manufacturing company I worked with bought a list of “verified opt-in contacts” from a data broker. Technically compliant – the contacts had opted into something. Practically disastrous – they’d opted into a generic “industry newsletter,” not emails from this specific manufacturer about industrial coatings. The campaign generated a 0.5% complaint rate and zero conversions. Worse, it trained their target market to ignore future emails, even legitimate ones.
The irony: their existing customer list, which they’d been neglecting, had a 38% open rate and 0.02% complaint rate. They were investing in purchased lists while ignoring the engaged audience they’d already built.
When More Emails Mean Less Revenue
Over 160 billion spam emails are sent daily. Your marketing team is competing for attention in that environment by… sending more emails. The logic breaks down immediately.
I analysed sending patterns for a SaaS company convinced that frequency drove conversions. They’d escalated from weekly to daily emails over six months. Revenue per subscriber dropped 40%. Why? Subscriber fatigue, increased unsubscribes, and promotional overload that trained users to ignore all their emails. When they finally sent a critical product update, open rates were 8% – users had learned to delete without reading.
We restructured their email strategy around permission-based segmentation. Only users who explicitly wanted daily deals received daily emails. Product updates went to everyone. Educational content went to engaged segments. Result: overall revenue increased 60% while sending 70% fewer emails. Complaint rates dropped to 0.05%.
Every email you send either builds or erodes permission. Send too many, and recipients revoke that permission – by marking you as spam or simply ignoring you. Both outcomes are equally fatal to your email programme.
Culture Problem Behind the Technical Failure
The real issue usually isn’t technical – it’s cultural. Companies develop aggressive sending cultures where volume becomes the primary KPI. Sales targets drive email calendars. Nobody wants to be the marketer who “left money on the table” by not sending that extra campaign.
This manifests predictably: overlapping campaigns hitting the same subscribers, poor segmentation treating all contacts identically, ignored unsubscribe requests (the 10-day CAN-SPAM window becomes “we’ll get to it eventually”), and list purchases justified by “everyone does it.”
GDPR penalties can reach €20 million or 4% of global annual turnover. CAN-SPAM violations stack – that purchased list of 10,000 emails becomes over $500 million in potential penalties if prosecuted to the maximum. Most companies never face maximum penalties. But they face something potentially more expensive: permanent sender reputation damage.
Once major ISPs flag your domain, recovery takes months or years. Your legitimate emails – password resets, order confirmations, critical account updates – don’t reach customers. That’s not a marketing problem. That’s a business continuity problem.
The Questions Nobody’s Asking
Most email programmes fail not from lack of sophistication but from lack of governance. Nobody’s asking: Do we have actual permission to send this? What’s our current complaint rate? How many people marked our last campaign as spam? When did we last clean this list?
These aren’t technical questions. They’re strategic ones. And if your marketing team can’t answer them immediately, you’re probably closer to the spam line than you think.
The uncomfortable truth is that permission in email marketing isn’t binary – it exists on a spectrum, and it erodes with every irrelevant message. Someone who enthusiastically opted in three years ago may now consider your emails unwanted clutter. Their inbox has changed. Their needs have changed. Your value proposition needs to justify continued attention, not assume it.
If you’re uncertain whether your email programme is building relationships or burning them, that uncertainty is itself the answer. Book a consultation to audit your email programme before your next campaign becomes your last one. We map permission architecture, complaint patterns, and compliance gaps – not to limit your sending, but to ensure what you do send actually reaches inboxes and drives revenue.
Our Email Marketing services focus on sustainable programmes that grow engagement over time – because the alternative is watching deliverability collapse and wondering why your “aggressive outreach” stopped reaching anyone.
