This is late, but do you remember how he got his mailing list off of HN? -He started an interesting experiment about starting a business from scratch, and planning to reach X thousand dollars of income per month in only a few months. "The Web-App Challenge" or something.

That was a very interesting project, so I signed up for updates. Not long after that, his e-mails started being mostly about selling ConvertKit to us, interspersed with useful(-looking?) articles. I can't help but feel like selling ConvertKit was his goal right from the start, and that the web app challenge was just a ruse to get us to receive his sales pitches. This is very clever, of course, but it's sleazy too.