The instaplay samples from somewhere in the middle of a representative song are what makes this work so well, I think.
It's striking how different it feels compared to MusicMap from the sibling post (which is also neat): MusicMap plays the entire song from the start, so it takes a while for each song to get going. The YouTube embed also takes a second or two to initialise.
Every Noise at Once, on the other hand, gives you a fairly good idea what a genre or artist is a about the moment you click the link. Very similar to Ishkur's Guide in that regard!