A user wrote a blog post about Readbetter

It's an amazing feeling to see people use a product that you built - it's even cooler when users turn into mini evangelists. That happened to me when one of my earliest users (who I didn't know in any way before) published a blog post about my service: https://gustavosouza.blog/automatically-send-substack-newsletters-to-kindle/

It's since driven a bunch of users to Readbetter.