WASHINGTON - An avalanche of intelligence leaks from former CIA contractor Edward Snowden sent shockwaves around the world in 2013, lifting the lid on a vast global spying network and raising fears of a surveillance state.
As the year drew to a close, the 30-year-old Snowden remains exiled in Russia, his final port of call following a worldwide game of cat-and-mouse that appeared to come straight from the pages of a spy novel.
A traitor to some, a heroic whistleblower to others: Snowden's disclosures have shed light on intelligence-gathering methods which shocked many through their sheer scale.
Tens of thousands of documents leaked by Snowden to The Guardian newspaper and other media outlets have detailed the nature of the National Security Agency's (NSA's) hitherto shadowy activities.
The fugitive Snowden, Time's runner-up behind Pope Francis for its person of the year, told the magazine he hoped the leaks would lead to greater transparency by governments.
"What we recoil most strongly against is not that such surveillance can theoretically occur, but that it was done without a majority of society even being aware it was possible," he said via email in a rare interview.
Tons of metadata gathered
Snowden's revelations made it clear that metadata and information from millions of emails and phone calls - incidentally, some of it about American citizens - has been systematically raked in by the NSA.
Civil rights groups decried the NSA's activities as the actions of a Big Brother-like government, trampling on the rights of individuals with little oversight.
The repercussions have been felt far and wide.
President Barack Obama in August promised reforms to improve "transparency" while at the same time stating that many of the NSA programs were a necessity.
Washington has also had to soothe anger amongst its allies, particularly after revelations that the NSA had targeted German Chancellor Angela Merkel's phone.
Yet according to some analysts, the long-term consequences of the Snowden revelations remain to be seen.
James Lewis, an expert in technology and public policy at the Center for Strategic and International Studies in Washington, questioned whether there would be a fundamental change in the practices of the intelligence community.
"You're not going to see major changes," said Lewis, estimating that opponents of the programs remained a "noisy minority" of around 20-25 percent of voters.
"I think the majority of the American people would rather see programs that are more transparent and have greater oversight in exchange for smaller risk of attack," he said.
Lewis believes the problem is that "people have never appreciated the difference between collect and read."
"Nobody can sit down and read 70 million emails but you could get machines to identify those with links to terrorism or proliferation," he said.
One of the programs set up under the 2001 Patriot Act allows for the collection from US phone companies of metadata, such as numbers called and the time and duration of calls.
The gathering of such data from ordinary Americans sparked outrage in the United States and led Congress to try to rein in the NSA.
Gordon Adams, an expert on defense and national security at American University, says the NSA was given unprecedented freedom following the September 11, 2001 attacks.
"In a climate of fear we basically took the reins off of accountability for the intelligence community," Adams said.
"The reality is the law gave them (NSA) immense running room and they have seized every inch of that running room and then some."
Another NSA program known as PRISM involved gathering up data on the Internet activities of millions of people worldwide using information gleaned from US technology giants such as Apple, Microsoft, Google and Facebook.
It prompted the companies to issue an appeal to the United States and other governments to reform their surveillance practices. A statement from the companies said Snowden's revelations "highlighted the urgent need to reform government surveillance practices worldwide."
"The balance in many countries has tipped too far in favor of the state and away from the rights of the individual," the companies said.
US allies angered
But the revelations concerning the US intelligence community's snooping on allies, while embarrassing, were unlikely to do lasting damage, according to Karen Kornbluh of the Council on Foreign Relations think tank.
"International reactions abroad were surprisingly muted because foreign leaders are aware that their security intelligence services engage in similar activities," Kornbluh said.
The bigger threat, Kornbluh said, was "to the health of the Internet itself," warning she feared a "Balkanization" of the web.
"The revelations may provide a rationale for some foreign governments grappling with ongoing economic as well as privacy concerns to exert more domestic control over data flows," Kornbluh said.
So far, only one percent of the 58,000 documents provided by Snowden have been disclosed, according to an official from The Guardian. But CSIS analyst Lewis believes the worst may be over for the US government.
"My sense is that the broad outlines are so well known that it's hard for them not to repeat themselves," Lewis said.
"It will be hard to come up with more dramatic revelations. They will be able to release specific details that would do incredible damage to the collection programs but in terms of political effect, it's already largely been achieved."