The impressive Election Day ground game that swept President Obama to victory was fueled by a technological edge left over from his initial run to the White House in 2008.
The result was high turnout among specific demographic groups responsible for Obama’s first win — African-Americans, Latinos, young voters and women.
While both campaigns blanketed swing-state television airwaves with advertisements, outside observers said Obama’s treasure trove of data helped give him a notable edge over Republican Mitt Romney.
After laying the groundwork more than four years ago, Obama's camp was able to analyze the data it culled from supporters in 2008 to hone its message and micro-target its ground effort.
Obama's campaign had amassed an email list of roughly 13 million supporters from 2008. That meant it could send out test messages to some people on that list to see which email subject lines or keywords made more people open the messages or donate to the campaign.
Former Massachusetts Gov. Mitt Romney, on the other hand, was coming off of a grueling Republican primary battle and had to launch his online and social-media presence during the general election from scratch.
"They had to spend most of their campaign fighting the primary, so the amount of time they had to specifically target and match their message to individual voters and to learn from it was limited," said Andrew Rasiej, the founder of the Personal Democracy Forum, an organization that tracks the intersection of technology and politics.
The Obama campaign "had a major advantage because when you're building big data resources, the longer you're collecting data, the longer you're analyzing data … the smarter the data becomes over time," he said.
The potent combination of data from social media and its email list enabled the Obama campaign to build a profile of potential voters and frame a compelling get-out-the-vote message, both online and off the grid.
"They train their volunteers to have a message at the door that's targeted toward that person at that very moment,” said Rasiej.
Zac Moffatt, the Romney campaign's digital director, said his 120-person team had to employ a different online strategy than the Obama campaign because it was coming off of the Republican primaries.
"They had more resources and they didn't have a primary," Moffatt said. "There was a substantial outspending of dollars online."
Comparing the two campaigns' digital strategies, "it's more like apples to hamburgers," Moffatt said. "It was a very different process to get here.
"Republicans from 2008 had not embraced digital," Moffatt said. "We had to build a plane while flying it, so we were constantly learning new things."
Still, Moffatt said, the Romney campaign had voter-engagement levels on Facebook that were on par with or higher than President Obama's this past fall.
"What we did in just six months is more impressive than what they built in four years, and I think that's a story that's missed," he said.
An Obama campaign official acknowledged that the head start helped, adding that the campaign was able to build on the platform from the previous election.
The official said the campaign also leveraged a variety of social-media tools to target various demographics. It used the online bulletin board-style tool Pinterest to reach out to women and the blogging site Tumblr to target young voters.
"We were very whimsical on there," the campaign official said. "We were willing to take risks to get our messages across to be relatable to young people using quality design and clear messaging."
An incumbent president will have a leg up on any challenger because the incumbent has more time to analyze the data about his or her voter base from the previous election and first term, according to Rasiej.
"In the 21st century, the candidate with [the] best data, merged with the best messages dictated by that data, wins," he said.
— Amie Parnes contributed to this report.