Researchers at University College Dublin's fantastically-named "Clique Research Cluster" have traced the birth of musical trends via a Last.fm API. The team took the listening preferences from users across hundreds of cities to discover where certain tracks first gained popularity, and how that popularity spread across the world. Although still true to an extent, the findings show that the populations of big cities like New York and Los Angeles are no longer the trend-setters in what is an infinitely more connected world. If deciphering graphs which pitch "Normalized Coldplay" against "Normalized Radiohead" is your thing, the full paper is a fascinating read.