People at Medium love charts. People show charts during all-hands meetings, they rotate charts on TV screens around the office, they send charts to each other. So at some point Mike and Evan made a nice little internal tool called Charted. After a little while Mike approached me about open sourcing Charted and making it a service. As someone who loves maintaining software I agreed and after a couple months of work we introduced Charted to the world. Charted is still used within Medium and I still maintain its open source version.