Sidechain Compression in Ableton Live 8
via AbletonInc:
Huston Singletary explains and demonstrates the popular “pumping and breathing” effect used on countless electronic and dance tracks. Live 8’s intuitive Compressor-Sidechain effect is explained and a custom preset is created in the studio showing the characteristics of this classic audio effect.
It has actually been used for over thirty years now dating back to analog consoles like SSL's and analog compressors with key inputs-way before Flying Lotus or any other new age type of trip-hop/techno composers came around. Don't hate, it's a great effect and mix tool that has many different applications.