My two cents.

The first time I read this post was two years ago. I was working a problem: how to practice Japanese. I had users and revenue, but no growth. Simple maths told me my product would never grow as a startup, and I had no way out of the niche. This post helped me confirm my worry: my market is too small.

What I learned: add a filter to the problem I want to solve. Is the problem big, or is it going to be big? This is expecially important when I am working on something I am passionate about. There is confirmation bias and wishful thinking when it comes to what I love.

Now I am working on a problem I care about, and the problem is big.

This post expresses an idea that I can easily relate to, given my experience. In this sense, it is useful.