This is probably the most ambistious personal project I've built to date, but something I am deeply passionate about.
My thesis was that music is becoming increasinly hard to share and when someone sends me music I will probably forget to listen unless:
Catalog was meant to provide native inbox to Spotify - it literally would just add to an designated "inbox" playlist on your account. If you did open the app you could see metadata about who sent something and an optional message, but this was not the core experience.
I consider this on-going work, but the direction may very well change