Every Noise at Once by Paul Lamere

Every Noise at Once (everynoise.com) is an algorithmically-generated, audio-annotated, dynamically evolving map of the music genre space. It arrays the 700+ major music genres tracked (so far) by The Echo Nest (the.echonest.com) in a readability-adjusted scatter-plot by the genres' aggregate audio characteristics.
The X axis moves from dense and atmospheric music on the left to choppier, bouncier, sharper music on the right. The Y axis moves from highly organic and acoustic music at the bottom to highly synthetic and mechanized dance forms at the top. The visual weight of each genre is determined by how actively its songs are currently being played, bought, reviewed and discussed online.