There's a lot of promising work ongoing exploring emergent music genres. Just recently, two scholarly articles came out in the same week: "Genre Complexes in Popular Music" in PLoS ONE, looking at MySpace (http://dx.doi.org/10.1371/journal.pone.0155471), and "Follow the Algorithm: An Exploratory Investigation of Music on YouTube" in Poetics (https://dx.doi.org/10.1016/j.poetic.2016.05.001)