So far, I shared the newsletter with a few friends and people I met online. I have also submitted it to Hacker News and got one subscriber right away. Other than that, no promotion at all.
The feedback is enthusiastic, and I can't wait to publish another article on market size considerations. Before I will do so, I set my goal to have 20 subscribers on the list before I do so. Just three more and I'm good to go ✌️