[mtmail]

Does your newsletter have a "Welcome user number 1234"? or similar, like a number in the URL? Ages ago I used a similar approach to gain data on growth of a website. They would increase a number in the URL for every (shopping) checkout session, easy way to figure out if there was growth or not.

[lai-yin]

Thanks for the suggestion. There is no visible counter on the webpage for users to see, and I'm not seeing one when I look under the hood in DevTools. I could be missing something though. It still would be odd since given my industry and where this user works, I don't see much incentive for him to track my subscriber growth.