For a few surreal minutes, a mere 12 words on Twitter caused the world's mightiest stock market to tremble.

No sooner did hackers send a false Associated Press tweet reporting explosions at the White House on Tuesday than investors started dumping stocks — eventually unloading $134 billion worth.

The U.S. army is working to limit its dependence on GPS by developing the next generation of navigation technology, including a tiny autonomous chip, the director of the Pentagon's research agency said Wednesday.

DARPA, the research group behind a range of spy tech and which helped invent the Internet, was also the driving force behind the creation of the Global Positioning System, director Arati Prabhakar said at a press conference.

A Pew Research Center report released late Wednesday indicated that online social networks have become political hotspots in the United States.

Approximately 39 percent of U.S. adults engaged in political activity in Internet communities during the 2012 U.S. presidential campaign, according to a Pew report titled Civic Engagement in the Digital Age.

Samsung said Thursday that unexpectedly high demand for its latest flagship smartphone, the Galaxy S4, was behind shipping issues that delayed scheduled sales in the U.S. market.

"We are experiencing difficulty in boosting supply in the short term because pre-order demand has been far stronger than we anticipated," said Lee Don-Joo, head of sales and marketing at Samsung's mobile unit.

Apple on Wednesday announced that its annual Worldwide Developers Conference will take place in San Francisco in June.

In an unusual move, Apple gave a one-day notice that tickets would go on sale for what is considered a must-attend event for software wizards interested in conjuring up applications for iPhones, iPads, iPods, or Macintosh computers.

When Apple launched its iTunes music store a decade ago amid the ashes of Napster, the music industry — reeling from the effects of online piracy — was anxious to see how the new music service would shake out.

"The sky was falling, and iTunes provided a place where we were going to monetize music and in theory stem the tide of piracy. So, it was certainly a solution for the time," said Michael McDonald, who co-founded ATO Records with Dave Matthews and whose Mick Management roster includes John Mayer and Ray LaMontagne.

Samsung's latest flagship Galaxy smartphone goes on sale this week, as the South Korean giant seeks to cement its lead over faltering rival Apple in an increasingly saturated market.

The Galaxy S4, armed with eye motion control technology that will pause a video when the user looks away, comes with a faster chip and is thinner and lighter than the previous S3 model.

More than 10 million Dutch citizens were unable to use their official online signature to pay bills and taxes because of a cyberattack, officials said Wednesday.

The national DigiD system "is no longer accessible since Tuesday evening because of a DDoS attack," the interior ministry said in a statement.

A self-proclaimed leader of the LulzSec international hacking group has been arrested in Australia, police said on Wednesday, after charging him with attacking and defacing a government website.

The 24-year-old IT professional, who went by the online identity "ozshock", was seized at his office in a town 76 kilometers (47 miles) north of Sydney on Tuesday.

Hackers spooked markets Tuesday after breaking into the Associated Press's Twitter account and falsely reporting President Barack Obama had been injured after two blasts at the White House.

A brief alert on the news agency's @AP account read: "Breaking: Two explosions in the White House and Barack Obama is injured."