Every now and then I scroll through my "Recently Added" tab on iTunes, going all the way back to when I first started ripping .mp3s in the 7th grade. I'll see that time I went on a 12-month Memphis rap binge in college. Or when I came back from 5 months in London and was suddenly "into" dance music. One of my favorites is revisiting the summer where I started to really dig through Madlib samples.
Huge blocks of my life are mentally categorized by the music that I listen to. For me, Lettermans is a way to make that timeline public while sharing conversations with my favorite artists. For you, it's hopefully a reliable place to learn something new.