Ask HN: How would you promote a song digitally?

Tiktok.

https://www.businessinsider.com/the-beaches-blame-brett-vira...

https://www.rollingstone.com/pro/features/tiktok-video-app-g...

https://blog.symphonic.com/2025/09/11/how-to-make-money-on-t...

https://routenote.com/blog/tiktok-has-the-power-to-make-arti...

Get it to appear on TouchTunes, go around popular bars in the local clubbing areas and insert it on the playlists hourly.