Welcome to 21 st century elections, where prospective voters interact with candidates not just at town halls across early primary states, but also in 140-character bursts of opinion on Twitter, an online money transfer through a candidate's web site, or the click of a "like" button on Facebook.

As social media allows voters to get ever-closer to the candidates, it is also allowing politicians to learn more than ever before about the people that could elect them.

"Lots of folks are tracking candidates based on their activity on Facebook because it's a place with 800 million users and a forum whereby they express their interests and opinions on range of topics, not the least of which is politics," said Warren Getler, vice president of global communications at data analysis group MicroStrategy.

In New Hampshire , where about 250,000 people are expected to cast their primary ballots today, Mitt Romney is winning the Facebook game.

About 31 percent of the Granite State's "politically active" Facebook users- those that have "liked" at least one political page - are Romney fans, according to data aggregated from the 3.5 million Facebook profiles using the   Wisdom Application, a tool developed by Microstrategy.

Ron Paul has the support of about 25 percent of the 142,000 Facebook Wisdom users in the first-in-the-nation primary state. About 15 percent "like" Gingrich and Huntsman and Santorum each have about 11 percent of those "likes."

Those trends are true nationwide as well. Romney is dominating his GOP opponents in his overall number of Facebook fans, with 1.3 million users "liking" his page. Paul comes in second with about 706,000 likes, according a Facebook data analysis from the independent media analytics group  Socialbakers.

With his near-victory in the Iowa caucus, Rick Santorum has seen his Facebook fan base swell by 107 percent over the past month, according to the Socialbakers analysis. The second-fastest growth - 14 percent - was on Paul's page.

But, as Republican digital strategist Patrick Ruffini points out, sheer numbers of fans matter far less than how active those fans are.

When it comes to online interaction, Romney takes the cake with nearly 220,000 interactions (mentions, likes, shared links, etc…) in the past month. Paul is again in second-place with 137,000 interactions.

"The bottom line number probably isn't what matters; it's how many on a routine basis are interacting with the candidate online," Ruffini, a strategist with the Republican political consulting agency Engage,  said.

In an election where a mere eight votes can separate the winners from losers, as they did in the Iowa caucus, candidates are taking the new wealth of data available about these online fans and translating it into tailored campaign messaging and placement.

"For years politicians have been trying to figure out, 'How do I better target voters?'" Ruffini said. "Social data I feel like would enable that in much more real-time sense."

For example, if Newt Gingrich wanted to run a television ad attacking Ron Paul in Charleston, South Carolina, that would most likely been seen by Paul supporters, he may want to run it during "The Daily Show."

The Wisdom data shows that Paul's Facebook supporters are more likely to watch Jon Stewart's Comedy Central program than the average Facebook user.

But if Gingrich wanted to target Mitt Romney fans, the Wisdom data shows he may want to run his anti-Romney ad on HGTV or during the show CSI as Romney's Facebook fans are more  likely to "like" those programs on Facebook.

This type of Facebook analysis is like an "instant polling tool," Getler said.

"It provides efficiencies so that campaigns can be targeted and not waste time and go to the people they need to reach," he said.