Definition: flash mob

A group of people who gather at a predetermined time and place to perform a silly prank such as yelling at the top of their lungs for 30 seconds and quickly dispersing before the police arrive. Using cellphones, the venue can be changed if the first one is compromised. Why do they do this? Just for fun.

Flash mobs are also organized on the spot for political rallies as soon as some controversial event takes place.

Spontaneous, Fast Communications
The flash mob is quickly organized by email, blogs, texting and social networks, and messages can be forwarded several times to increase its size. Bill Wasik, senior editor of Harper's Magazine, claimed to organize the first successful flash mob in New York in the summer of 2003. A hundred people gathered in Macy's rug department to shop for a "love rug," saying they all lived together and made purchases only as a group.

Flash mobs that are not always peaceful have been reported in Boston, Brooklyn and other cities; however, they seemed to occur more frequently in Philadelphia in 2010. All of a sudden, gangs of rowdy teenagers would appear in a store or on the sidewalk and push their way through the crowd injuring some onlookers. Commenting on his original purpose of encouraging spontaneity, Wasik lamented that the flash mobs in Philadelphia had turned violent.

The Flash Dance
A flash mob can break into song and dance, perhaps not very much choreographed, but fun nevertheless. A major attempt to set up flash dances is Tom and Gary's Decentralized Dance Party (DDP), and by the end of 2012, the two Canadians organized more than 50 of them. Using an FM transmitter in a backpack along with an iPod and microphone, they broadcast to dozens of boom boxes in the vicinity that have been tuned to a designated and unused radio channel.

The Flash Rob
Across the U.S., flash mobs have been quickly organized to rob a store. All of a sudden, dozens of teens appear in a retail establishment and begin stealing merchandise from one end of the place to the other.