Spotify - Map shows when two people play same song at same time
Mochi - Write notes and flashcards with Markdown and study them with spaced repetition.
SOUNDS - Discover music with friends
Zorbi - Spaced-Repetition Flashcards - Other tools are built by boomers, Zorbi is built by students.
Songlink - Share music with anyone.
Yak Tack - remember. words.