From Stark Effect: A "mic in track" is a recording made on a PC...record from the microphone input of the PC's sound card and save the recording in mp3 format. The default filename is "mic in track" followed by a number."
Basically that means someone else's home recordings that YOU can download. Type "mic in track" into a peer-to-peer network (KaZaa, etc) and you can download/eavesdrop someone reciting poetry, personal messages, practicing the bongos, anything else people do with a microphone on - the audio of equivalent of Peeping Tommery.
Stark Effect has brilliantly created a series of remixes from his collection of these recordings, ranging from the sublime ("Think Of Me") to the ridiculous ("Eeples and Beeneenees.") "Bunnyrabbits, Satan, Cheese and Milk" was even named Best Remix of 2002 by radio WFMU. And they should know. Dozens of raw, unedited m-i-t recordings are available as well, such as "14," a dramatic 10 minute phone conversation between a former boyfriend and a troubled 14-year-old mother. Yikes.