Sometimes known as bootlegs this now infamous style of music has been around aslong as it has been poosible for anyone to get their hands on a mixer and/or recording software and learn how to use it.
The Style was first seen in Ibiza where DJ's would mix and old fave song with a new song - bringing fresh new sound. Recently the style has progressed massivly with people like "Poj Masta" starting to use "Aphex Twin" style mixing programmes to produce the slickest glitch and bootleg tracks the world has ever seen.
Others say that this style has only just become popular - mainly becuase of the RIAA's constant copyright grabbing. As bootlegging is Illigal it is still officially a crime - but most artists mind this less as some people feel inclined to buy their music after hearing a really good bootleg / Bastard Pop remix.