The term critical mass is said to have originated in the field of epidemiology where it describes a phenominon where the spreading of an infectious disease can reach a point beyond any local ability to control it from spreading more widely. Marketers use the term to denote a threshold that, once reached, will result in additional sales. The term critical mass is comparable to the term tipping point where a tipping point is a critical point in a system’s development that defines where positive feedback will gain traction leading to rapid and irreversible state change.