Of specific concern, though, is that several organizations, including the London Stock Exchange and Barclays Bank, were targeted during the anticapitalist demonstration by teams of hackers from Indonesia, Israel, Germany, Canada and the U.S. For five hours, at least 20 companies were subjected to more than 10,000 hacker attacks.
This technique is called Floodnet, after a legal software program that initiates a large number of Web searches every second. Multiply this by tens of thousands of people coordinating their searches to constantly occur over a period of hours, and you find yourself under a distributed denial-of-service attack.
Winn Schwartau, "Hactivists' cyberdisobedience is anything but civil," Network World, September 13, 1999