See these posts: Map of Musical Genres (1264 genres, the map itself): Are musical genres real and constraining or are they mixing together polymorphically? (17 genre clusters).Now that music genres have been unhitched from the centralised broadcast media, and now genre labels are not ordered through TV, weeklies and radio, the possibilities have suddenly opened for music to be ordered in new ways. One of the key changes here is that music cultures are now largely self-organising. Genre labels might still be dreamed up and created by industry insiders, journalists and artists, but they are more often the product of interaction through social media. The tagging processes that are used to classify music are now performed and attached by those with an interest in consuming the music. This has opened up the potential for music genres to proliferate, expand and develop, for sub genres and even sub-sub-sub genres to spiral, and on other occasions for genres judged irrelevant to wither into uncoolness.To take just one popular meta-genre, metal, we find the massive variety of sub-genres associated with this one genre alone are quite unfathomable, the suggestively labelled ‘math metal’ is indicative of this fragmentation within genres. The result of this new type of musical categorisation is that music cultures become self-organising things. This self-organising system is open to rapid change, to increasingly granular and microscopic genres and genres within genres, and to the fragmenting of musical categories around small differences. To understand music we need to focus a little more on how these cultures are organising themselves.This is an impressive and revealing set of practices that tell us much about how people identify with music, how they differentiate their music and themselves from other people and how music can be understood as it becomes a part of people’s lives. Here we have something close to collective action as real-time social media enable responsive classifications of everyday culture. I’ve focused upon music here, but this is now touching lots of cultural spheres.