As the U.S. presidential campaign took shape this week, Mitt Romney's staff made what it hopes will be a momentous move: Ann Romney, the candidate's wife, joined Twitter.

Romney made her debut on the social networking site Wednesday in response to a Democratic strategist who said the former Massachusetts governor's wife had never worked a day in her life.

I made a choice to stay home and raise five boys, Ann Romney said in her tweet. Believe me, it was hard work.

Twitter has become the sparring ground of the 2012 campaign, where verbal fisticuffs fly and campaigns test the strength of their opponents, all within the 140-character limit per message.

It's become an instant source of spin for political operatives eager to guide coverage in the media and turn voters' attention to issues they think will help the candidate.

It's also now home to damage control as two of the lead voices of Democratic President Barack Obama's re-election campaign, senior adviser David Axelrod and campaign manager Jim Messina, quickly posted their own messages Wednesday night in support of Ann Romney.

For the Romney campaign, which has turned its focus to beating Obama in the November 6 election after its chief Republican rival dropped out this week, Twitter was the smartest way to quickly present Ann Romney's point of view.

That message needed to be shared in real time, said Zac Moffat, Romney's digital director. A response was warranted. Mrs. Romney felt that that was the case. I don't know if a press release would have found the same value at the same time.

The campaign earned praise for its quick thinking.

All year long I've been astonished by how slow the Romney campaign has been to pick up any prowess at all on social media, Democratic strategist Joe Trippi told Fox News. But last night, they really came out very quickly, creating this new Twitter handle for Ann Romney. The staff jumped on it and pushed it. It was a totally different campaign last night.

In the past, Mitt Romney's operatives haven't shied from fights on Twitter.

Earlier Wednesday, Romney spokeswoman Andrea Saul and Obama spokeswoman Lis Smith traded barbs over the Romney campaign's assertion that 92 percent of job losses in the recession hit women.

In January, Obama adviser Axelrod and Romney adviser Eric Fehrnstrom went a few rounds before a Republican debate in South Carolina.

Dude, none of my business, but shouldn't you be in debate prep instead of trying to explain yourself to me? Axelrod wrote.

Ha ha! Believe it or not, the economy is an issue where we don't prep Mitt, he preps (you), Fehrnstrom replied.


That fighting spirit permeates Twitter itself.

A December 2011 study from the Pew Research Center found that comments about Mitt Romney were far more negative on the social networking site than on blogs or in the overall news media.

Romney is not the only one who gets beat up on Twitter. The Pew study found that Obama's negative evaluations outweighed positive assessments 3 to 1.

Romney's camp doesn't just use Twitter and social media to argue with the opposition. It's also become a place where the multimillionaire private equity executive can show some just-folks authenticity.

During the primary, Romney used Twitter to broadcast his affection for Jet Blue airlines and Subway sandwiches. Over Easter weekend, the campaign posted a photo of Romney painting Easter eggs with his grandchildren on the mobile photo sharing site Instagram.

In March, Romney's body man, the young aide who shadows the candidate's every move, signed onto Twitter to provide behind-the-scenes videos and pictures of the campaign.

Romney's sons are active on Twitter, too. Last week, Tagg Romney let the world know that he objected to the Mad Men television show calling his late grandfather George Romney, the former Michigan governor, a clown.

In the Internet Age, presidential campaigns often are channeled through the latest online innovation.

In 2004, Democrat Howard Dean showed new possibilities for online fundraising. In 2008, with a Facebook founder at the helm of his digital team, Obama showed the power of social networks for political campaigns.

Now Twitter has emerged as the leader in shaping the message of campaigns. It also deserves credit for the campaign's lightning pace.

Obama joined Twitter in April 2007, but it wasn't until this election cycle that the site fully emerged as a force in presidential politics.

Republican Newt Gingrich, a futurist at heart, chose to use the site to announce his candidacy for president. As Gingrich's fortunes rose this winter, the Romney campaign invented a variety of Twitter-based ploys to hammer the former U.S. House of Representatives speaker.

While Romney has outpaced Republican rivals at the polls, he has struggled to keep up with some of them online.

Gingrich has 1.4 million followers on Twitter; Romney has 430,000. More than 14 million people follow Obama's Twitter messages. (All trail pop star Lady Gaga, who has more than 22 million followers — equal to the population of Australia.)

Not everyone has taken to the social media campaign.

Twitter has a more prominent place at campaign headquarters and in newsrooms than in most American homes. In a recent Pew Research Center, one in 20 Americans surveyed said they sometimes or regularly get news about campaigns from Twitter.

I think Twitter is more for inside-baseball people, said Keith Nahigian, a Republican strategist and veteran of multiple presidential campaigns. Some of it is so boring.

(Editing by David Lindsey and Eric Beech)