About half an hour ago, NORAD sent out an ominous looking tweet with the words "NORAD jets intercept..." and a link. The only problem? If you clicked on the link it brought you to an FAA error page with no more information.
Luckily, it was nothing serious. Two F-16s had intercepted a general aviation aircraft that had been out of communication in a restricted area over Washington, D.C. The aircraft resumed communication and everybody went about their business.
Breaking news on Twitter that turns out to be false or simply doesn't have the proper context can do real damage. For instance, when the Associated Press was hacked in April of 2013 a tweet was sent out reading, "Breaking: Two Explosions in the White House and Barack Obama is Injured." The AP quickly said that it had been hacked, but not before the financial markets went into a tailspin, thanks in no small part to high-frequency trading computers.