Issue #251 All About Email

Hi, {{first_name|friend}}. 👋

Welcome to Issue #251 of All About Email!

Last week, I celebrated a huge milestone for this newsletter, and one that I never thought would even be possible. I reflected, celebrated and made some predictions after 250 issues!!! 🎉

This week, we are back with another summer guest author. Robert Brandl has built this awesome Chrome Extension (I use it), and that comes with a serious amount of data. Let’s see what the email platforms behind 16,655 brands can tell us.

Let’s go! 👇

For years, I answered that by digging through raw email sources. Then I got tired of it and built a free Chrome extension that does it for me.

It's called Email Detective, used by more than 700 people already. It anonymously records which platform sent the email, how quickly it arrived, and where it landed.

📊 That's now added up to:

So I pulled the data. Some of it confirmed what I expected. Some genuinely surprised me.

(Quick note: this is what our users' inboxes show, not a perfect census of the internet. But it's a big enough pile to spot real patterns.)

Here are seven things worth knowing. 👇

Here's the top 10 by number of brands:

🍌 Mailchimp is still the name everyone's aunt has heard of.

But 45% more brands use Klaviyo, and the backstory explains why:

🚨 Here's the twist. The two platforms that send to more brands than any other, including marketing tools, are:

Both beat Klaviyo, and either is an "email marketing" tool the way we usually mean it.

🛠️ They're transactional infrastructure. The quiet plumbing your dev team wires up for password resets, order confirmations, and shipping updates.

Looking at high-volume senders, Amazon SES actually pulls ahead of SendGrid: nearly 25,000 email sightings compared to SendGrid's 22,270.

Here’s a funny observation. You would assume market leader Klaviyo also uses its own product for its own email marketing.

💡 They do, but:

I'm not here to dunk. There are usually real reasons (lifecycle email, sales, and marketing owning different systems).

🧠 But it's a good reminder that "best tool for the job" isn't always "the tool we sell," even within the companies that sell it.

This one's less fun and more important.

😬 45% of brands have no enforced DMARC. Their policy is set to "none" or missing entirely, which means it monitors but blocks nothing. The other 55% are configured to prevent domain spoofing.

And to be clear, most of that 45% isn't made up of brands skipping DMARC entirely:

Either way, to a spoofer, "none" and "no record" look the same.

🔓 The door's unlocked. If you do one thing after reading this, check your own domain's policy.

You've probably heard that open rates run a bit inflated because of Apple's Mail Privacy Protection, which auto-loads images (including the tracking pixel) whether someone actually opens the email or not.

💡 What's less known: the opposite also happens. If images don't load, the tracking pixel never fires, and that open never gets counted, even though a real person is reading the email right now.

Thanks to Email Detective, we know how often that happens:

🧠 Here's what that means in practice:

🚨 So a dashboard showing 40% is probably closer to a real open rate of 43%. Not a huge gap, but it adds up.

Everyone doing email marketing has a sense that Outlook is stricter about spam than Gmail.

💡 Now there's a number: roughly 13% of email users' opens landed in spam in Outlook during our testing, versus 1.8% in Gmail. Roughly 7-8x higher.

Broken authentication makes it worse everywhere, but the stakes are much bigger on Outlook. Brands with weak or missing DMARC saw close to 20% of their mail land in spam folders.

🚨 Even brands with solid auth still lost about 9%, several times Gmail's rate for brands with no enforcement at all.

ℹ️ Our Outlook data is newer and smaller than our Gmail data, so this will get more precise over time.

But if a meaningful chunk of your list reads on Outlook, this is your reminder to actually check your setup there instead of assuming what works for Gmail carries over.

🔮 Remember when AMP for Email was supposed to revolutionise the inbox? Interactive carousels, live forms, the works?

I'm not saying it's useless. I'm saying almost nobody has decided it's worth the engineering effort. File it next to the other "future of email" promises that quietly never arrived.

Every number above came from Email Detective.

It's free, it lives inside Gmail and Outlook, and when you open any email, you'll see the platform that sent it, the auth setup (SPF, DKIM, DMARC with alignment, BIMI), the template builder, delivery time, and even the sending IP.

🪄 Handy for competitive research, deliverability checks, or just being nosy about the brands you follow.

👉 Grab Email Detective for Gmail or Outlook.

And if you spot something the data can't explain, let me know! I'm always digging.

Thanks for having me, Simon. 🙏

​

This is not a sponsored post, and I genuinely use the Chrome Extension. In fact, I was able to use it to show Knak why their marketing emails were going straight to my spam:

🚨 It is important to note that this data comes from the user base of the Chrome Extension, and it’s not necessarily representative of the wider email ecosystem, but still it has some excellent datapoints:

See you next week, {{first_name|friend}}. 👋

Every week, as I write this newsletter, I'll share the track of the moment to create an unbelievably eclectic playlist just for your inbox.

🚨 If you’re interested in sponsoring the “All About Email” newsletter, you can find all the details in this Google Doc.

This week's excellent and insightful email news & tips:

If you have any questions about this email or email marketing, please reply, and I will get back to you as soon as possible.

I hope you have a great week! 👋