Yeah, I thought the dozens, from street corners in the 30's/40's I think, were the origins of the diss-rap/MC battle. Does the dozen number have any connection to 12-bar blues?"the dozens" - hyming insults, used by kids in the states, often aimed at you opponents mum.
Anyone know or care to speculate if the boast rap also came from the dozens or Jamaica? Or even if they both have a common African origin?