Short answers, pulled from the story.
The term "disc jockey" was ostensibly coined by radio gossip commentator Walter Winchell in 1935 to describe the radio work of Martin Block. The phrase first appeared in print in a 1941 issue of Variety magazine.
Engineer Shuichi Obata at Matsushita (now Panasonic), based in Osaka, Japan, invented the first direct-drive turntable. Matsushita released it in 1969 as the SP-10, the first in their Technics series. The Technics SL-1200, introduced in 1972, became the turntable most associated with hip-hop and turntablism.
DJ Kool Herc developed a technique he called "The Merry-Go-Round," in which he isolated the percussive "break" section of a record and extended it by switching between two record players. This allowed him to stretch a short musical section into what he described as a "five-minute loop of fury."
DJ Dr. Motte started the Love Parade in 1989 as a small demonstration for "Peace, Joy, and Pancakes" (Friede, Freude, Eierkuchen) with 150 people. By its peak in 1999, the event drew an estimated 1.5 million attendees.
Nightclubs record average sound levels between 93.2 and 109.7 dB, and three-quarters of DJs have tinnitus. DJs also face tenosynovitis from repetitive scratching and cueing motions, and complications from prolonged standing over four-to-five-hour sets, including varicose veins, joint compression, and cardiovascular disorders.
The DJ Mag Top 100 DJs poll began in 1991 as a journalist-selected ranking in the British magazine DJ Magazine. It expanded in 1993 into a Top 100 list created to mark the magazine's 100th issue, and in 1997 it transitioned to a public vote, allowing readers worldwide to participate.