Associated Press' twitter account gets hijacked. Intruder posts, "two explosions in the White House and Barack Obama is injured". The tweet was only visible for a matter of minutes, but the Dow Jones industrial average took a nose dive.
Anyone still thinks, cyberwar is science fiction?
Update 25-Apr-2013:
Some rocket-science theory (for me) that this news did not have that big an impact. However, this theory still confirms there was some impact.