Short answers, pulled from the story.
The word crunk first appeared in print within a 1972 Dr. Seuss book titled Marvin K. Mooney Will You Please Go Now!. The author used the phrase Crunk-Car without providing any definition for the term at that time.
Lil Jon became one of the key figures in popularizing crunk during 1998 and 1999 before signing to TVT Records in 2001. Three 6 Mafia started making original music distinctive for its spare low-BPM rhythms and simplistic chants while other artists like Ying Yang Twins White Dawg Bone Crusher and Lil Scrappy from Atlanta also helped popularize the genre.
An archetypal crunk track features layered keyboard synths and drum machine clapping rhythms alongside heavy basslines. Shouting vocals often appear in a call and response manner throughout these songs while Roland TR-808 and 909 drum machines usually accompany simple repeated synthesizer melodies.
The song Get Low performed by Lil Jon & the East Side Boyz with the Ying Yang Twins reached number two position on the chart. It spent more than 21 weeks inside the charts overall and Busta Rhymes and Nelly accepted offers to perform on remixes of Get Low despite previously avoiding Southern hip hop associations.
The term evolved to take on a negative stigma involving police parents and media outlets throughout the 2000s. Mainstream media began publishing stories where the word referred to crazy and drunk criminals while law enforcement agencies started using the term to describe criminal behavior associated with intoxication.