In this frame grab from video provided by the Herman Cain campaign, campaign manager Mark Block smokes a cigarette in an ad. Before Smoking Man, there was Obama Girl. And who can forget Jib Jab? The new ad showing Block is the latest political video to become an overnight web sensation. The ad, showing Block take a deep drag on a cigarette while Cain flashes a Cheshire cat grin, has had close to 1 million clicks on Cain's website since its debut last week. It's also been aired repeatedly on cable news shows and become the subject of countless parodies. (AP Photo/Herman Cain 2012)

(AP) -- Before Smoking Man, there was Obama Girl. And who can forget Jib Jab?

A new ad featuring Herman Cain's smoking campaign manager Mark Block is the latest political video to become an overnight web sensation. The ad, with Block taking a deep drag on a cigarette while Cain flashes a Cheshire cat grin, has had close to 1 million clicks on Cain's website since its debut last week. It's also aired repeatedly on cable news shows and become the subject of countless parodies.

Online viral videos have become a staple of American politics. Not long ago, pricey paid were the only way for candidates to be noticed. Now, anyone with a good idea and an Internet connection can generate buzz in the presidential contest.

"The most important thing to appreciate about viral videos is they really reduce the power of traditional media gatekeepers," said Stephen Farnsworth, an associate professor of communications at George Mason University in Virginia. "The decisions of what the public could see used to be in the control of TV executives. The Web gives people the ability to send messages horizontally. You see something you like, you put it on YouTube."

Some widely disseminated videos have been harmless fun such as the ad produced by digital studio Jib Jab in 2004 showing rivals George W. Bush and singing a hilarious rendition of "This Land."

Others have had a deeper impact, including Tina Fey's scathing depiction of 2008 Republican vice presidential nominee as an ill-informed lightweight. Those sketches first appeared on NBC's "Saturday Night Live" but were widely shared online.

Cain, a little-known former Godfather's Pizza executive before joining the 2012 GOP race, has seen his popularity spike recently after a series of debates and his much-discussed 9-9-9 tax plan. The smoking man ad, with its low production values and quirky imagery, has added to the sense of novelty about Cain's candidacy and was distributed almost for free.

In an interview with CNN on Friday, Block said Cain had raised $3 million in October in part because of the video's popularity.

"That's what we're seeing in our grassroots activism growth and obviously in the YouTube thing," Block said.

President Barack Obama, cast as the innovative newcomer when he joined the Democratic field in 2008, has experienced the upside and downside of being a Web video sensation.

The Obama Girl video, in which a fetching young woman sang about her crush on the then-Illinois senator, went viral early in the campaign and reinforced the notion of Obama as the cool and sexy alternative to his more established Democratic rival, New York Sen. Hillary Rodham Clinton.

Clinton briefly reclaimed the online spotlight when news footage of her welling up at a New Hampshire coffee shop was widely circulated. She narrowly beat Obama in that state's first-in-the-nation primary.

Obama fans struck back with the "Yes We Can" video, produced by the Black Eyed Peas singer will.i.am and featuring celebrities such as actress Scarlett Johansson. It was an online hit and revived Obama's image as the hip and trendy candidate after he lost New Hampshire.

Arizona Sen. John McCain, Obama's general election rival in 2008, sought to turn such gushing testimonials back on the Democrat. Strapped for cash that summer as a confident Obama toured Europe, McCain's campaign released a video comparing Obama to starlets Britney Spears and Paris Hilton.

"He's the biggest celebrity in the world," the ad said mockingly. It quickly went viral and became the talk of cable news.

Obama's campaign also experienced a crisis when videos surfaced of his former pastor, the Rev. Jeremiah Wright, shouting anti-American slogans from the pulpit. The videos generated questions about Obama's faith and status as the first major black presidential candidate, forcing him to deliver a major speech on race relations.

The campaign later found itself on the defensive again after news clips of Obama fist-bumping with his wife, Michelle, were widely distributed, as well as a sound bite from Michelle Obama saying her husband's candidacy made her proud of the United State "for the first time in my adult life." Critics seized on the videos as evidence of the Obamas' "otherness" or lack of patriotism.

Ken Goldstein, whose Campaign Media Analysis Group tracks political advertising, said that while online videos had the power to influence a race, paid television advertising still carried much more overall impact.

"The Internet preaches to the choir," Goldstein said. "It's a great way to raise money and mobilize supporters to work harder, which are not trivial things. But viral videos are not a way to mobilize passive and undecided voters, which television ads do."