A little over a year ago, my close friend and I decided it would be a fun experiment to start a collaborative playlist on Spotify. We had been sharing music for many months, sending songs in inboxes and chats, but we struggled to keep track of the tracks as our conversation diverged. We wanted a semi-permanent space to retain our varied musical interests over time. It would be a scrapbook of sorts, an arena for us to indulge our nostalgia as well as discover new content in the days before “Discover Weekly” became popular. And so, “Friends,” the playlist, was born as an endearing effort to keep the mixtape culture alive during the age of digital music.