The stunning news of Osama bin Laden's death didn't come from a major media company. It came from a tweet. When the White House announced Sunday night that the president would issue a 10:30 p.m. address to the country, speculation surged about whether U.S. officials had killed Libyan leader Muammar Qaddafi, Bin Laden or any number of other "national security" targets. But on Twitter, a message by Keith Urbahn, the chief of staff of former defense secretary Donald Rumsfeld, tilted the rumors in favor of bin Laden.

"So I'm told by a reputable person they have killed Osama Bin Laden," he wrote. "Hot damn."

CNET's Greg Sandoval is calling it a major turning point for citizen journalism. "Tonight's news was by far the weightiest story that Twitter has ever helped break," he wrote. Interestingly, while Urbahn's tweet carried great weight in the U.S., it wasn't the first Twitter account to actually break the news.

That honor goes to an IT consultant who identifies himself as Sohaib Athar under the Twitter handle "ReallyVirtual." About 12 hours ago, Athar began live-tweeting the attack from Abbottabad, the town where bin Laden was killed. "Helicopter hovering above Abbottabad at 1AM (is a rare event)," he tweeted. That would have been at about 3:30 p.m. ET on Sunday. He continued tweeting about the operation, having no idea about its significance.

  • “Go away helicopter – before I take out my giant swatter :-/”
  • “A huge window shaking bang here in Abbottabad Cantt. I hope its not the start of something nasty :-S”.
  • After the president's announcement: “Uh oh, now I’m the guy who liveblogged the Osama raid without knowing it.”
  • “For the people who are trying to email me to reach me, I simply can’t filter out the notifications from the emails :-( “

The fact that Osama bin Laden's death was live-tweeted is almost too astonishing to believe. Yet the tweets and the timestamps are right there for anyone to see. Reporters have not yet confirmed Athar's identity but it will certainly be fascinating if and when he comes forward.