Hunted as a US traitor and at the center of a diplomatic row, Edward Snowden got off to a less spectacular start in life: he is a self-confessed geek and high school dropout.

Snowden, 30, who Friday told human rights activists in Moscow that he wanted to claim asylum in Russia, came out of nowhere to trigger one of the biggest intelligence leaks in American history.

Yet until he shot to notoriety by revealing details of vast US surveillance programs, Snowden had made little mark on his world.

His classmates remember him as a quiet, blonde-haired boy glued to his computer screen. He left high school at 15 without graduating, but remained fascinated by computer technology.

He had a small, tight-knit circle of friends where he lived near Baltimore, Maryland, and together they built personal computers, lived and breathed the Internet and enjoyed Japanese anime.

"He was a geek like the rest of us," one friend told the New York Times. "We played video games, watched anime. It was before geek was cool."

Snowden quickly moved into the online world, adopting an avatar he named "The TrueHooha," and from 2003 spent hours playing online games and wandering through forums and chat rooms.

From 2007 to 2009, he left hundreds of comments on the chatroom of Ars Technica, a tech news website, where a picture emerged of someone "always being sure of himself, sometimes to the point of seeming arrogant."

"He often thought he was the smartest guy in the room, and he let others know it," Ars Technica wrote.

"Snowden was frequently someone ready to go to the mat for his beliefs -- even when no one was on his side. And he could be abrasive."

Snowden joined the US army in 2003, saying he wanted to fight in Iraq. But he never made it there after breaking both legs in a training accident, leading to him being discharged from the military.

He then got a job as a security guard for the National Security Agency (NSA), one of the largest and most secretive of the US intelligence agencies.

But in 2006, the young computer geek somehow managed to win an information technology job with the CIA despite lacking formal credentials. From there he was sent to Geneva with a fat paycheck and a diplomatic cover.

On Ars Technica he opined on everything from the cost of bottled water and hamburgers in the Swiss city to his observations of life in Europe.

But he also showed early libertarian leanings, backing the ideas of then presidential hopeful Ron Paul to go back to the gold standard. He also made two $250 donations to Paul's campaign.

He criticized social security saying "somehow, our society managed to make it hundreds of years without social security just fine."

In one revealing conversation, Snowden angrily took issue with a 2009 New York Times report about US actions in Iran which was based on classified information.

"You don't put that shit in the NEWSPAPER," he wrote, adding that the anonymous sources spilling the beans "should be shot in the balls."

In 2009, he left the CIA and rejoined the NSA in Japan, although he rarely mentioned his job in his online conversations.

In 2010, he returned to Ars Technica after a long absence with increasingly political posts. "Society really seems to have developed an unquestioning obedience towards spooky types," he wrote.

Three years later he shot into the spotlight, revealing the NSA's acquisition of phone logs and data from nine Internet giants, including Google, Microsoft and Facebook, as well as secret global hacking operations.

Snowden had taken flight to Hong Kong after three months in his new job with the consulting firm Booz Allen Hamilton as a systems administrator based at the NSA's threat operations center in Hawaii.

"My position with Booz Allen Hamilton granted me access to lists of machines all over the world the NSA hacked," Snowden told the South China Morning Post newspaper. "That is why I accepted that position about three months ago."

With him in Hawaii was girlfriend Lindsay Mills, 28, who in a personal blog cheerfully described herself as "a world-traveling, pole-dancing super hero." The blog has since gone offline.

Having made his revelations, Snowden headed unaccompanied to Hong Kong, carrying four computers, the New York Times said, and copies of secret documents.

In an interview with the British daily The Guardian, Snowden described himself as a "whistleblower" and tried to explain why he had decided to lift the lid on the secret surveillance programs.

"For me, there was no single moment. It was seeing a continuing litany of lies from senior officials to Congress... that compelled me to act."

When former vice president Dick Cheney, a key player in the US decision to invade Iraq, denounced him as a traitor, Snowden shot back: "Being called a traitor by Dick Cheney is the highest honor you can give an American."

He added: "Ask yourself: if I were a Chinese spy, why wouldn't I have flown directly into Beijing? I could be living in a palace petting a phoenix by now."

Checking into a Hong Kong hotel, but without a plan, Snowden contacted lawyers and human rights groups, and soon found an ally in Wikileaks founder Julian Assange, himself holed up in the Ecuadorian embassy in London to avoid extradition.

He proceeded to Moscow on June 23, two days after his 30th birthday, just as Hong Kong asked Washington for more details to back up its request for Snowden's extradition to the United States.

But he got no further than the transit area of Moscow's Sheremetyevo Airport, from where he sent out asylum applications to 27 countries. Venezuala came back with an offer of "humanitarian asylum," which he passed upon.

"He's anxious about the next step ... but feels really good about the debate he provoked," Glenn Greenwald, the American lawyer turned journalist who reported Snowden's revelations in the Guardian, told AFP this week.

"He's very calm, without any fear and definitely happy about the choices that he made," he said.

[Picture released by Human Rights Watch shows US National Security Agency (NSA) fugitive leaker Edward Snowden (C) during a meeting with rights activists.]