I'm impressed at how this guy's channel has taken off. The first version of this (a static backboard optimized to put as many shots into the hoop as possible)

I'm impressed at how this guy's channel has taken off. The first version of this (a static backboard optimized to put as many shots into the hoop as possible) was posted here, and he had something like a few hundred subscribers and a few hundred views. That video now has 4M views and he has 82k subscribers. He deserves the subscribers, as the rest of his videos are great, but I'm curious as to which medium got the most viewers. HN? (Seems unlikely to me.) Reddit? Twitter? The Algorithm?