Four years ago, Barack Obama kicked off his presidential campaign on the steps of Illinois' Old State Capitol, speaking in front of thousands of supporters and a throng of media. Earlier this month, when he formally announced his re-election campaign, he did so without public appearance, in an online video.

The shift in part represents the difference between the candidacies, from one starring an upstart challenger to one featuring an incumbent president. But it also underscores how dramatically social media have become a defining force in modern-day politics.

Obama is not alone. Former Massachusetts Gov. Mitt Romney announced his Republican presidential bid April 11 in a low-key online video, a stark contrast to his splashy 2007 announcement at the Henry Ford Museum in Dearborn, Mich.

When former Minnesota Gov. Tim Pawlenty jumped into the GOP race, he did it by posting a video on Facebook. After California Democratic Gov. Jerry Brown broke off budget talks with Republicans, he took his case directly to California voters on YouTube. Potential Republican presidential candidates Sarah Palin and Rep. Michele Bachmann of Minnesota turned to Twitter to slam the federal budget agreement.

"GOP: don't retreat! The country is going broke. We can't AFFORD cowboy poetry & subsidizing abortion," Palin wrote.

The numbers provide motivation: Voters are increasingly turning to such sites to learn about politics, with more than 1 in 5 doing so before November's midterm election, according to the Pew Internet & American Life Project.

But embracing new technology has its dangers. A prime example emerged during California's 2010 Senate primary, when GOP candidate Carly Fiorina released a YouTube video that portrayed an opponent as a man in a sheep suit with blazing red eyes, loping in a pastoral field.

"Carly Fiorina got click-throughs, but so do train wrecks," said Thad Kousser, a political science professor at the University of California, San Diego. "You want people to be watching in delight - not horror."

Politicians have long adapted to new platforms to press their agendas, from Franklin D. Roosevelt's embrace of fireside chats on the radio in the 1930s and 1940s to John F. Kennedy's use of television decades later. Adoption of online innovation has occurred much more rapidly.

In 2000, GOP presidential hopeful John McCain pulled in $500,000 in donations via the Internet in the 24 hours after his surprise win in the New Hampshire primary, a novel infusion of cash at the time. Three years later, Democratic hopeful Howard Dean's supporters used Meetup.com to fuel his insurgent run.

It was Obama's 2008 strategy that changed online campaigning. He used social media for such diverse tasks as connecting grass-roots supporters in vital early states and revealing his vice presidential pick by text message.

"Pre-Obama, the political world viewed digital as a box that had to be checked," said Bryan Merica, a GOP new-media consultant. "What Obama did was show this is a tool we can use to not only fundraise but win elections."

Patrick Ruffini, another new-media consultant, described the 2008 Obama campaign as the "gold standard."

"Republicans, after that campaign, we were kind of licking our wounds, wondering how we could do this better," he said.

They have since learned; the "tea party" movement was built in part on social media connections, much as Obama's campaign.

Ruffini cited the Internet's role in the 2010 election of Massachusetts Republican Scott Brown, delivering $12 million in donations in the 18 days before he captured the Senate seat that had been held by the late Democrat Edward M. Kennedy.

"Digital ... made a game-changing difference in the race," said Ruffini, whose firm worked on the Brown campaign and is now working for Pawlenty.

Among the most remarkable users is Palin, who routinely posts notes to her nearly 3 million followers on Facebook in order to bypass what she calls the "lamestream" media.

"I can't think of any time in American history where the vice presidential candidate on a losing ticket has been so iconic two, three years after the election," said Paul Levinson, a Fordham University social media expert. "That's because Sarah Palin uses Facebook and all these new media quite effectively."

Even the trendiest tactics are not always effective. Obama's re-election video received about 430,000 views on YouTube. A mocking retort by the National Republican Senatorial Committee - featuring clips of Obama playing golf and partying with celebrities such as Paul McCartney before ending with a cartoon of the president riding a flying white unicorn with a rainbow emanating from the creature's rear end - drew more than three times as many.

Pawlenty, who initially required people to "like" him on Facebook before they could see his video, got only 5,000 new supporters on a site that has more than 500 million active users, although his video has been seen by more than 100,000 people.

In California, Brown's YouTube video attracted 20,000 views, a paltry figure in a state with 37 million residents.

But such efforts allow politicians to reach out to their most ardent supporters before their messages are broadcast more widely through traditional channels.

"What better people to talk to on your first day as a candidate than those people who are going to carry your message forward to the broader community?" Ruffini said.

Obama's emphasis on social media in his first campaign left him with a treasure trove of millions of cellphone numbers and email addresses. Those supporters were the first to be formally notified of his re-election bid and directed to a website listing local Obama events, volunteer opportunities and ways to donate money.

Pawlenty has the most sophisticated site of any likely GOP contender. In addition to biographical and fundraising pages, the site includes a section where supporters earn points and badges for volunteering, recruiting friends and other forms of assistance.

Other potential GOP challengers are working feverishly to create a strong online effort, in part to establish credibility for their own candidacies.

"Otherwise, they're just going to be swamped and counted out before they even start," Levinson said.

Explore further New Republican Party 2.0 website unveiled

(c) 2011, Los Angeles Times.

Distributed by McClatchy-Tribune Information Services.