In 1979, Sugarhill Gang a notorious rap group that was produced by Sylvia Robinson released a Hip-Hop track called "Rappers Delight".
Besides appealing to a wider audience the single track recorded over 2 million copies in sales within the United States which earned Sugar Hill Records approximately US$3.5 million.
This realization of how much money could be made from rap became the tipping point for rap which moved from being street music to a commercial commodity.
Since then, rap has become sophisticatedly commercial with lots of rappers who have gone on to sell millions of albums in a week. Eminem is currently the highest-selling solo rapper of all time.
TU increases with an increase in consumption of a commodity as long as MU is positive. In this phase, TU increases but a diminishing rate as MU from each successive unit tends to diminish. ... When consumption is increased beyond the point of satiety, TU starts falling as MU becomes negative.
