66% of spam complaints came from one easy-to-fix mistake

Welcome back to the 128th edition of Nord Media

​​Fun fact: The average Klaviyo account is sitting on THOUSANDS of invisible landmines.

There are outdated segments, fake profiles, and spam-prone flows.

By the time Q4 rolls around, that toxic data can lead to suppressed deliverability, poor inbox placement, and wasted ad dollars.

It’s like trying to PR your half-marathon time while still hungover from the night before.

You might finish, but it’s going to be messy.

This is why now is the perfect time to hit reset, and we have the exact solution.

In this email, we’re breaking down:

• What’s causing most brands’ flows and deliverability to silently suffer

• How dirty identity data sneaks into your Klaviyo account and quietly damages performance

• How to run a Summer Email Detox with Customers.ai that protects your revenue and inbox health before Q4 hits

Let’s dive in 👇

What’s causing most brands’ flows and deliverability to silently suffer

You can have the best flows in your industry and still end up in Gmail’s spam tab.

That’s because deliverability isn’t just about email design or send frequency anymore.

It’s about data quality.

And most Klaviyo accounts are sitting on months, sometimes years, of invisible buildup:

• Profiles created from junk data or unreliable visitor ID tools

• Segments bloated with unengaged contacts

• Automations are being sent to people who never truly opted in

It doesn't always look broken. Open rates may still seem healthy, and flows might still be converting, but behind the scenes, your sender reputation is eroding.

Your emails start hitting spam folders.

You get quietly rate-limited by inbox providers.

Klaviyo throttles your sends to protect your domain.

None of these issues screams for attention. They just compound silently until Q4 rolls around, and suddenly nothing’s hitting like it should.

How dirty identity data sneaks into your Klaviyo account and quietly damages performance

Since we've seen the damage low-quality data can deliver, the question becomes, how does that happen?

One of the most common sources of toxic data in Klaviyo is your website visitor ID tool.

Many tools enrich your profiles by matching anonymous visitors to emails, but when those matches are inaccurate or low-quality, they silently poison your account.

Here’s how the damage creeps in:

• Profiles are created using mismatched or incomplete data

• These profiles get added to your segments like any other subscriber

• Automations trigger flows to people who never truly opted in

• Over time, spam complaints increase and deliverability declines

This process is difficult to catch because everything looks fine at a glance. 

How to run a Summer Email Detox that protects your Q4 revenue

Holiday performance doesn’t start in November. It starts with the data you’re collecting right now.

Bad identity data silently poisons your Klaviyo account, triggering automations to the wrong people, inflating complaint rates, and crushing deliverability when it matters most.

We’ve been testing Customers.ai, a high-accuracy identity resolution tool, with our clients… 

And the results have been undeniable:

Higher flow revenue, fewer complaints, and a much clearer view of who’s actually shopping.

Here’s how to run a proper detox with Customers.ai and give your email engine a clean slate for Q4:

1. Identify the source of bad data

• Start by reviewing where your new profiles are coming from.

• If you’re using a visitor ID tool, check for signs of mismatch or inflated volume.

• Audits have shown some tools inject low-quality contacts that trigger flows and complaints.

2. Monitor your complaint patterns

• Look for time periods where spam complaints suddenly increased.

• If complaints cluster around a specific integration, that’s a red flag.

• In one case, a brand saw a 90% drop in complaints after switching identity providers without changing a single email.

3. Suppress or clean toxic segments

• Don’t wait for Klaviyo’s auto-suppressions to kick in.

• Actively prune low-intent segments, remove inactive profiles, and rebuild from verified, high-quality contacts.

4. Upgrade your identity resolution strategy

• We’ve been testing Customers.ai with clients, and the results speak for themselves.

• Flow revenue went up, spam complaints dropped, and our visibility into who’s actually shopping became much clearer.

That kind of clarity matters. In head-to-head tests against other providers, Customers.ai delivered:

• 3x higher identity match accuracy

• 15x more revenue per ID

• Up to 5x fewer spam complaints

It’s the only visitor ID solution we’ve seen that backs performance with real proof, not inflated match rates or vague reporting. 

If you want to clean your data, protect your domain, and go into Q4 with confidence, this is where we’d start.

Final Thoughts

The email results you want in Q4 depend on the data you clean up in Q3.

It only takes a few months of bad data to damage your sender reputation, hurt deliverability, and slow down flows that used to print money, but with the right tools, it's fixable.

We’ve seen strong early results using Customers.ai to clean up identity data for clients. 

Higher match accuracy, lower spam complaints, and better flow performance without changing the creative. 

If you’re looking to run a proper detox, this is a great place to start.

Get ahead now, and your email performance won’t just survive the holidays, it’ll be ready to scale.

Want to learn more? Connect with me on social 👇
LinkedIn • Instagram • Twitter 

Thank you for reading! I appreciate you.

Sincerely,
Kody

Disclaimer: Special thanks to Customers.ai for sponsoring today’s newsletter.