Another point that writers often miss when researching sites is that different sites have different audiences. Substack readers are generally looking for terribly serious writers who write terribly serious newsletters. My more lighthearted political pieces wouldn't work there. They work fine on Medium which has a different audience. As you know, I write gardening articles on HubPages. Those articles wouldn't work well on either Medium or Substack, but they do great on HubPages. Again, different audience.