It's unfair he didn't include the name of the app in the article (or it's unfair that I can't see properly, if he did). I want to see what this problem was he was trying to solve!
The author posted a comment here about that, and that this article is about https://benji.so/ . Sounds like HN comments were persuasive in releasing the app that triggered the article.
Comment: https://news.ycombinator.com/item?id=40872817