During the 2008 presidential campaign, people on YouTube consumed a billion minutes of Barack Obama campaign videos. That adds up to almost 2,000 years.
This year, Obama and GOP presidential candidate Mitt Romney are on the way to leaving that figure in the dust. The campaigns are constantly releasing new Web videos.
Lee Rainie, who directs the Pew Research Center's Internet & American Life Project, remembers when the rule for successful online videos was repetition.
"The old conventional wisdom was that you had to hammer home the same message consistently a lot of times before it would actually sort of penetrate the consciousness and begin to shape the opinion of voters," Rainie says.
Now those days seem quaint. Today it's all about constant stimulation, everywhere, all the time.
"People's attention is so fragmented, their sources of information are so fragmented, that consistency doesn't necessarily have the same power that it might have had in days gone by," Rainie says.
Campaigns can easily churn out a new Web video every day — and they often do. But that doesn't guarantee that they have an audience.
"A lot of these videos only have a few thousand views on YouTube," says Colin Delany, founder and editor of the website Epolitics.com. "Often they're not getting seen by a mass audience."
The viewership can be small, but it includes people with big megaphones.
For example, Whoopi Goldberg of ABC's The View recently talked about an ad on air: "A controversial new campaign ad for President Obama strongly implies that Mitt Romney wouldn't have made the call that led to a major victory in the war on terror."
That ad featured President Clinton reflecting on the raid that killed Osama bin Laden, saying, "You hire the president to make the calls when no one else can do it."
The Obama folks never bought TV time for that video. But millions of people saw it anyway because it landed in their inboxes or on their Facebook pages.
"It's a way to drive a message," says Brian Jones, who advises the Romney campaign. "You're not actually paying for anything other than the production value of the Web ad. And they're usually pretty easy to produce, and you can do it pretty quickly."
So if Romney talks about Latino voters one day, there's a Web ad bolstering that message. And if the next day, Obama slips up and says the private sector is doing fine, then you get an ad contrasting that statement with people talking about how they're struggling.
"I have to work part time in order to make ends meet," one woman says in a Romney video. A man adds, "Sometimes I feel like I'm a failure." The ad reads: "No, Mr. President, we are not 'doing fine.'"
With every new video, the campaigns learn more about what works and what doesn't.
Benjamin Edelman of Harvard Business School says Google has mastered this approach with its advertisers. The search engine advises companies to try as many variations on an ad as they can think of.
One version might advertise "Boston Red Sox tickets." Another might say, "Buy tickets to a Red Sox game."
"It's not unusual for an advertiser to have hundreds or even thousands of different ads. Just churn them out in a variety of variations where you try every substitution of this word and that word and see what consumers seem to respond to," Edelman says.
The same is true in political Web videos. You might not think it makes any difference whether a candidate wears a white shirt or a plaid shirt. But it does, Edelman says.
"Now, you add something very different — like a different script, different look on the face, different body language — and the responses truly can differ by just an awful lot," he says.
Today, instead of paying a consultant tens of thousands of dollars to opine on what works and hoping for the best, campaigns can afford to try a range of things and see what sticks.
Jones of the Romney campaign says his team is always learning and refining based on what spurs donations, volunteers and ultimately votes.
"We are able to monitor what people are looking at, what they're responding to from a fundraising perspective," he says. "And it's important for the campaign to obviously keep a close eye on that and look to see what trends are developing from a Web ad perspective."
The things that work may find their way into candidate speeches and TV ads with real money behind them.
Low production costs also mean the campaign can try off-kilter things they might not bother with otherwise.
But there are risks to experimentation.
The Obama campaign would not grant an interview with its digital director, Teddy Goff, but he recently gave a talk at Social Media Week, where he said: "In 2008, if we had been tinny or political or not local enough or not timely enough or if we just didn't strike the right emotional chords, that would have been bad and people might have disengaged.
"You know, in this election, they can not only disengage — they can disengage and then tweet about how disengaged they are."
Every campaign wants a video that goes viral. But the last thing they want is a clip that goes viral for the wrong reasons.
Copyright 2012 National Public Radio. To see more, visit http://www.npr.org/.