A Nerdlet is a short, one-sentence blurb about a song. You can add one to any song on the Music Nerds site; just go to the album page and each song has an input box underneath it. (You have to be signed in to see it.)
You can put whatever you want in the space, but you only have 100 characters (the “[song title] is” part doesn’t count, don’t worry). You can try to describe the song as you hear it, write something impressionistic, or whatever.