Who this was forA services business with a small sales team, sending cold email from a mixed estate of inboxes it had inherited.
Reply rates were low, and the team was reading that as a copy problem. So the fix on the table was new copy.
Copy is a fair first suspect. But nobody had checked where the emails were landing. Placement was assumed.
We ran a seed placement test across the whole sending estate before touching a word of copy. Seed inboxes receive a test send from every sending inbox, and each result gets logged by where it lands.
We published the results to a health tool the client can open any time.
The estate split in two.
That's the awkward bit. Mail sent through the relay mostly never reached an inbox, and the blended numbers still looked survivable. A good inbox group averaged against a bad one gives you a mediocre number, and a mediocre number gets blamed on the writing.
New copy wouldn't have fixed any of this. It would've gone to spam too.
The health tool stays live, so the client can check placement per inbox without asking us. The estate's size is tracked in the client's own database.
If your reply rate dropped and your first move is rewriting the sequence, test placement first. Tell us how your sending estate is set up and we'll tell you what we'd test first.
Related tools: SMTP2GO, BounceBan, Instantly, Domain Deliverability Checker, Inbox Placement Triage
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Client names are always kept confidential at MMG, so they have been removed from this case study.
Published February 24, 2026
Last updated April 22, 2026