Glad you like it! I've been listening to it nonstop.

The core is database of >9k songs tagged by mood (and a fun fact!). Coming up with the right 2 axes for the mood (solitary <-> social, chill <-> intense) took a few iterations. I think I need to get the number of songs to about 20–30k soon, to add more variety.

Then there's an algorithm to determine which song to sample given the mood/year combo and song attributes, which forms a radio schedule. You can see some of those song attributes by visiting a song's detailed page (click on the "now playing" marque text or visit /stats and search).

I've added keyboard shortcuts and the rest is just polish!

Thank you!! I've been wishing for this for years, to be honest, and happy to have finally built it.