Several homemade mash-ups — welding the music from extreme metal acts to the lyrics/melodies of pop/rap songs — have been posted online at this location. Included on the site are the following "collaborations":

ENTOMBED vs. OUTKAST
NAPALM DEATH vs. SHAKIRA
CARCASS vs. MISY ELLIOTT
PITCHSHIFTER vs. B-52s
TERRORIZER vs. 50 CENT

According to AOL Music, a mash-up is the result of two or more songs, typically of different genres, mixed together to create a completely new song. Recent advances in technology and sequencing software have taken the homemade artform from an underground phenomenon to a worldwide craze that has been embraced by mainstream audiences, as well as the Billboard charts.

A mash-up is made by taking one song's vocals and laying it over another's melody or rhythm track. The producer usually takes two songs with similar tempos and digitally edits the lengths and pitches to create a seamless fit. Creating a mash-up requires raw music tracks, computer editing software, and a strong knowledge of music structure along with a lot of creativity.

Most mash-ups you've heard have not been cleared by the record labels that own the rights to the songs and are, in fact, illegal. Technology helps this underground movement grow, with most mash-ups being circulated on the Internet via blog and file-sharing sites. While some artists, such as BECK, encourage producers to put a creative twist on their music, others go so far as to issue cease and desist orders to musicians who use their songs without permission. Time will tell whether or not record labels and artists will embrace the practice. Until then, the movement will be forced to remain underground.