The latest alarm was triggered by a fake tweet saying that the White House was bombed, prompting a U.S. market nosedive that ended minutes later when the Associated Press said its Twitter account had been hacked. In 2010
stocks plunged in a "flash crash" following aggressive sales of
stock-index futures by a mutual fund….
Wait..wait…there’s more at http://www.reuters.com/article/2013/05/19/us-futures-hft-idUSBRE94I0DG20130519