By Roberta Rampton

WASHINGTON, Jan 29 (Reuters) - High school teacher Jason Knoll came to the White House on Tuesday from Madison, Wisconsin, on a mission: to show his students that tweets can be used for "more than selfies at the mall," and that political Twitter can transcend petty snark.

He joined a diverse group of about 60 people chosen from thousands of applicants who explained in 140 characters or less why they wanted to be chosen as volunteers to live-tweet the State of the Union address.

They paid their own way to sit in a darkened White House auditorium, far from the pomp of President Barack Obama's speech on Capitol Hill - but close enough to experience the moment.

"I hope I tweet something profound tonight about the #SOTU to make it worth your time," Knoll, told his 400 followers, including his history and government students from Verona Area High School.

The Wi-Fi connection in the Old Executive Office Building left a lot to be desired, participants griped.

But the barrage of tweets from the "State of the Union Social" - a central part of the White House social media strategy for the speech - rolled down the computer screen like a blur on hashtag #SOTUSocial.

"Lots of 'hard work and responsibility can make dreams come true' in speech so far," Knoll tweeted, saying he wished Obama would focus more on foreign policy.

The tweet-up was bizarre at times - one participant tweeted a series of photos of an "Obama doll" asking questions. And there were a lot of "selfies" (self-portraits shot by camera phones) in front of the White House.

But Knoll and the group helped the White House generate buzz for Obama's plan in 2014, a year in which many of his fellow Democrats will face difficult re-election campaigns.

SECOND SCREEN

Obama's televised address reached 33.5 million viewers last year, according to Nielsen ratings - a huge number, but 36 percent less than his first address to Congress in 2009.

For those tuning in, many also look for a "second screen" experience on a phone or a tablet as they listen to the speech.

"It's like the reason you go to the movie theater. It's not just for the bigger screen, it's to hear other people laughing or gasping," said Elizabeth Breese, a sociologist and strategist with Crimson Hexagon, a social media analysis firm in Boston.

The White House group sent or retweeted more than 1,200 messages during the first hour of Obama's speech and more than 700 tweets in the hour following, said Breese, who monitored the group's output using her company's analysis software.

Their tweets were 17 percent positive, 75 percent neutral, and 8 percent negative, she said.

It was a friendly crowd - they cheered at Obama's applause lines and laughed when the camera panned across stony-faced Republican lawmakers.

LESS SNARK, LOTS OF NOISE

The White House has experimented with similar events before, but this year's State of the Union social is part of a weeklong rollout of quirky photos and viral videos designed to make Obama's speech more interactive than ever.

But unlike other parts of the highly controlled White House messaging strategy, the output of the social was up to its participants.

"When they come here, we invite and encourage them to share their experience, and they do so freely," said Kori Schulman, Director of Online Engagement in the White House Office of Digital Strategy.

A few tweets were pointed, but the tone was less snarky than in typical Washington twitter battles.

Mary Leschper - social media guru for the American Petroleum Institute, the oil industry's powerful lobby group - blasted a stream of positive facts to bolster Obama's message about the benefits of a U.S. drilling boom.

"Here are your jobs," she tweeted, linking to a study about how cheap natural gas is helping manufacturers.

Meanwhile, Holley Atkinson, 54, who worked on Obama's election campaigns and describes herself as a longtime progressive political activist, had the opposite message.

"Pipeline spills, train wrecks, methane emissions - not safe," said Atkinson, who uses social media to push for a ban on fracking in New York state.

Having both Atkinson and Leschper tweeting from the White House made for "a very interesting kind of social experiment," said Gary Bivings, a digital strategist at PCA & Co., a Washington communications firm.

But Bivings said he wondered if the messages ended up "stepping on each other," drowning out points the White House would rather have emphasized.

"It's really hard to make a dent in a very noisy environment," he said. (Reporting by Roberta Rampton; Editing by Caren Bohan and Jim Loney)