Andy Carvin, NPR's head of "social media" at NPR. On nice days Carvin prefers to work on the rooftop terrace of the NPR building (Ricky Carioti/WASHINGTON POST)

Hold on a second, says Andy Carvin mid-conversation, swiveling to his laptop. He taps away for a few seconds, as quiet as a squirrel. And then he’s back.

Carvin does this 20, 25, 30 times — it’s easy to lose count — an hour. It’s practically second nature now. Often, he doesn’t even interrupt what he’s saying; the typing and the talking happen simultaneously.

Carvin is tweeting, relentlessly. Seven days a week, often up to 16 hours a day. He once went 20 hours straight, pumping out more than 1,400 brief messages on his Twitter account, @acarvin. That’s his guess, at least. It’s easy to lose count.

Since December, Carvin, a social-media strategist at NPR in Washington, has become a one-man Twitter news bureau, chronicling fast-moving developments throughout the Middle East. By grabbing bits and pieces from Facebook, YouTube and the wider Internet and mixing them with a stunning array of eyewitness sources, Carvin has constructed a vivid and constantly evolving mosaic of the region’s convulsions.

At a given moment, Carvin may be tweeting links to fresh video from Libyan rebels, photos of street protests in Bahrain or the highlights of a NATO news conference. His followers, in turn, point him to more material — on-the-ground accounts of the government crackdown in Yemen, breaking reports from Tahrir Square, the latest from Jordan or Syria.

The result is a dizzying, nonstop ride across the geopolitical landscape, 140 characters at a time:

• March 31: “Extremely graphic video of a Libyan man with half his jaw blown off, giving a V for victory sign & trying to talk” [link to video].

• April 11: “Video appears to show victims of shootings in Baniyas, Syria. More cameras than there are corpses” [link to video].

• April 9: “At least 10 casualties from tonight’s assault in Sanaa. Can’t really tell who’s alive and who’s dead” [link to Yemeni photo on Facebook].

And so on, into the thousands. “Is this the world’s best Twitter account?” asked the Columbia Journalism Review about @acarvin last week.

Carvin’s high-beam focus on the region has attracted more than 43,000 followers, essentially the readership of a small newspaper. His flock has more than doubled since he started tweeting about the Middle East in December during the first stirrings of rebellion in Tunisia.

Among those following his prodigious output: Susan Rice, the U.S. ambassador to the United Nations, actress Morgan Fairchild and Chad Ochocinco, the Cincinnati Bengals’ oddball wide receiver.

“It was very clear to me in December that Tunisia would be a big deal,” says Carvin, a stocky 39-year-old who seems to be constantly clicking, tapping or typing, “but it never occurred to me that this could kick off something much, much bigger. My tweeting kind of revved up with it.”

There isn’t really a name for what Carvin does — tweet curator? social-media news aggregator? interactive digital journalist? — but that may be because this form of reporting is still being invented. By Carvin, among others.

“I see it as another flavor of journalism,” he says. “So I guess I’m another flavor of journalist.”

Carvin likens himself to a radio or TV anchor, introducing the experts, the pundits and reporters. The difference, he hastens to add, is that Anderson Cooper has to go to the scene of his stories — and eventually has to go to sleep.

Not Carvin, whose anchor chair goes where he does and whose metabolism seems permanently set on “Go!” Carvin spends his workdays at a bland cubicle at NPR’s headquarters, but his tweets come from wherever he is (his wife, Susanne, says his iPhone is “pretty much an extension of his palm at this point”). He live-tweeted the first attack on protesters in Bahrain while he waited in line at the men’s room in Zaytinya, the downtown D.C. restaurant. He sent updates while at a Duran Duran concert at the South by Southwest festival in Austin, and at a pirate-themed birthday party in Baltimore with his 4-year-old daughter in tow. He regularly tweets on the Metro during his commute to and from his home in Silver Spring.

It doesn’t seem at all surprising that he suffers from repetitive stress in his hands and wrists and wears a special pair of corrective gloves when he’s planted at his desk at work.

Oddly enough, the one place Carvin hasn’t tweeted about the Middle East is . . . the Middle East. Carvin has been to Tunisia, Egypt, Israel and several other countries in the region, but has not been back since 2005, a time before Twitter.

Even more oddly: Before the tweet gig came along, the closest Carvin came to professional journalism was co-producing a documentary with his wife about Thai kickboxing. He spent more than a decade after college as a Washington policy wonk, specializing in technology and educational issues for such outfits as the Corporation for Public Broadcasting and the nonprofit Benton Foundation, for whom Carvin headed a project exploring ways to close the “digital divide” affecting poor communities. In 2006, NPR hired him to help the organization’s journalists make use of new media such as Facebook and Twitter. Carvin started tweeting soon after Twitter launched in 2006, mostly as a way to stay abreast of the news and to keep in touch with friends.

Susanne Carvin, a former National Geographic researcher who raises the couple’s two young children, says she understands her husband’s dedication to the story and the nonstop nature of it. “A few years ago, he would have been glued to a desktop,” she says. “Now, since he can do it all on his [iPhone], he can go to the garden with us, be walking along, check in with his contacts overseas. . . . It has become so commonplace, and he does it so regularly that half the time I don’t even realize he’s online.”

The Carvins’ children, meanwhile, take daddy’s wired habits for granted; his daughter and son, who is 2 1 / 2, have accidentally tweeted when he’s left his laptop unattended. So have the family’s two cats.

Part of the attraction of social media, Carvin says, is how it can be used for crowd-sourcing, or tapping a group’s collective knowledge and experience. During the 2008 election, for example, Carvin marshaled his followers to fact-check the presidential debates and provide tips about polling-place irregularities.

The same technique helped Carvin get to the bottom of a story last month. When he heard from a follower that Arab news sources were reporting that Libyan dictator Moammar Gaddafi had attacked rebels with Israeli-made mortar rounds, Carvin thought the story sounded fishy. He found the reports had a superficial basis: The Facebook page of Al Manara, a Libyan expatriate news service based in the United Kingdom, showed a photo of a munition stamped with what appeared to be a Star of David topped with an odd multi-crescent shape.

“They ID it as Israeli,” Carvin tweeted. “Maybe, maybe not. Need help to ID it. Anyone?”

Within minutes, Carvin’s “tweeps” — his Twitter people — began piecing it together:

“81mm calibre — it’s not eastern. Probably British,” responded one follower.

Another found a photo of a British-made 81mm shell with the same markings. Still another noted that the star logo indicated that it was an illumination round and the crescent signified a parachute, which deploy on such rounds to slow their descent.

This was soon followed by links to photos of similar rounds manufactured in India and France. Another follower posted a page from a NATO weapons manual that instructed member countries to identify their shells with the star-and-crescent markings.

Carvin declared the story “debunked,” even as other news outlets, including Al Jazeera’s Arabic TV channel, continued to report the bogus link to Israel.

“In a lot of ways, this is traditional journalism,” says Mark Stencel, NPR’s managing editor for digital news. Except that Carvin “has just turned the newsgathering process inside out and made it public. He’s reporting in real time and you can see him do it. You can watch him work his sources and tell people what he’s following up on.”

Another benefit is the “social” part of social media — Carvin has developed hundreds of sources through the give-and-take of Twitter. One of his best sources about opposition activities in Yemen is a former Miss Universe Canada contestant, Maria Al-Masani, a member of a well-connected Yemeni family.

Carvin also befriended a Libyan named Mohammed Nabbous, a tech buff who had created a 24-hour live video stream to report on events there. While witnessing fighting near Benghazi last month, Nabbous was killed in the crossfire. Carvin lauded him on NPR as “a pioneer” of an independent Libyan press.

Despite the speed of delivery and breadth of material that Carvin musters every day, the form has its weaknesses. Carvin acknowledges that it’s difficult to know the full context of some of the information he transmits, such as the harrowing footage he linked to last week of a father encountering his dead and disfigured son in a hospital room. The video apparently was from Yemen, but much else — who shot it, under what circumstances and when — was hard to substantiate.

What’s more, Carvin doesn’t speak Arabic or Farsi, which means he must rely on his followers for translations. He’s also never met about two-thirds of the hundreds of sources he uses for tips and tweets.

Carvin candidly notes another potential pitfall: He’s far more likely to get information from rebels than from the regimes. “The majority of people online [in the Middle East] are young, better-educated and skew toward reform,” he notes.

All this makes some observers raise an eyebrow about Carvin’s work. “To have NPR appoint a senior strategist with full knowledge that they are publishing news or information based on tweets of unknown or unvetted sources is troubling,” says Adam Curry, a media critic and vet­eran technology blogger (and long-ago MTV veejay). “Who knows where some of this is coming from? I’m not saying Andy’s a bad guy or has an agenda. But I do think it’s worth asking what NPR thinks it’s doing.”

Actually, NPR thinks Carvin is creating something new. “What you’re witnessing is Andy’s effort to determine the veracity of what’s emerging,” says Kinsey Wilson, the head of NPR’s digital-media division. “It’s not positioned as the definitive sort of piece that you might hear on NPR. It’s a different form.”

In his defense, Carvin says he relies on sources who’ve proven to be reliable and drops those with dubious track records. He’s open about unconfirmed material, flagging some claims with a single skeptical word, such as “Source?” or “Evidence?”

Carvin’s followers also are quick to point out his misfires. When Carvin tweeted a link to what he thought was video of nurses ministering to a wounded girl, his followers jumped in. The girl wasn’t wounded, they told him, she was dead; the women were washing the girl’s body for burial according to Muslim custom. Carvin quickly corrected his tweet.

The key, he says, is disclosing what he doesn’t know and asking others to fill in the blanks.

“It’s a self-correcting mechanism,” he says. “I don’t want to think of myself as a wire service. It’s an open newsgathering operation.”

He pauses, just before plunging back into the Twittersphere once more. “A lot of the time,” he adds, “I’m raising more questions than I’m answering.”