n. A sharp and often overwhelming increase in the number of users attempting to access a website simultaneously, usually in response to some event or announcement.
2000
Also, epicRealm can help a Web site offer certain customers priority service, just as an airline lets its frequent travelers board the plane first. In the event of a "flash crowd" — a sudden storm of usage that leads to a burst of traffic — a site can direct people completing purchases to be served before those who are still browsing.
1999
Among other problems, the approach deals with events like 'flash crowds' on public Internet sites. This is where incidents, such as the US lingerie firm Victoria Secret's Webcast fashion show, or a surge of stock market activity, generates unforeseen activity levels.
1993 (earliest)
"Free services like those on the Internet can't continue indefinitely," said Alexis Rosen, the president and founder of the Panix service. Because informal news about events on the network flows so quickly through electronic word of mouth, what Mr. Rosen called "flash crowds" are beginning to appear with increasing frequency to instantly clog computer systems.
The mall riot was the first successful riot in twenty years. "The police can get to a riot before it's a riot," said McCord. "We call them flash crowds, and we watch for them."