What do you mean, Flash?

Flash is short for "Flash Action". "Flash action" is a hippie behavior that is popular all over the world recently, and it can also be regarded as a short-lived performance art. Simply put, many people who contact with the Internet agree on a designated place through SMS or bbs, do a designated but noticeable action at the same time at a clearly designated time, and then leave quickly. Also translated are "Smart Mob", "Mob", "flash mob", "flash mob" and "Smart Action Gang". The names are varied and confusing. Most of the planners of "flash mob" activities are anonymous, which varies from place to place. Bill, a cultural worker in new york, USA, started it. Some of them are purely funny, while others are regarded as social or political activities.