The latest example of a campaign using online video is also one of the cycle's most ambitious: On Monday, Barack Obama's campaign launched a new Web site and 13-minute documentary highlighting rival John McCain's involvement in the "Keating Five" scandal 20 years ago. Campaign manager David Plouffe e-mailed the video to supporters early that morning, urging them to forward it to friends and family.

While TV spots continue to target undecided voters in key battleground states, online political content is usually aimed at another, very specific, target audience -- the news media. (It was no coincidence that Plouffe's e-mail was sent out at 3 a.m. that morning, arriving early enough for the morning talk shows and right at the start of the week's news cycle.)

David All, a Republican Internet strategist and founder of the David All Group, a conservative Web agency, couldn't stress enough the influence such videos have on generating buzz for a candidate. "People sometimes confuse the viewership of Web videos," All said. "It may only get 300 views, but those 300 people are the most influential people in American politics."

This time, however, the Obama camp says it's hoping to produce a viral video that reaches far more than those 300 Washington insiders. Both the mainstream media and the blogosphere were generous with their coverage in the first 24 hours after the video was released, but Obama spokesman Nick Shapiro stressed that the documentary is not targeted to the base, undecideds or the media -- it's for everyone.

As of this morning, traffic figures seemed to back him up: A little over 48 hours since its posting, the video has already topped 1 million views on YouTube.

All interpreted the documentary's goal differently, however. "It's certainly targeted at the mainstream media and other influentials to muddy up the waters," he said. "It was an effective attempt to win the week's news cycle."

Steve Grove, director of politics and news for YouTube, distinguished between the candidates' Internet strategies, noting that McCain's focus has been on relatively polished Web-only versions of TV ads whereas Obama more often uses longer videos and clips from speeches and events to communicate with voters, the Keating documentary being the latest example. Both strategies have their advantages, according to Grove: Obama's off-the-cuff videos show he's "committed to providing an inside look at the campaign," while McCain's aggressive attack strategy has "undoubtedly" drawn viewers to his YouTube page.

Grove said he thought the Obama camp has been "more effective than any other campaign" in utilizing Web video. But he also noted that McCain's YouTube channel was the most viewed on the entire site during a two-week span in August after the release of the heavily publicized "Celeb" (subscription) TV ad and its more caustic online counterpart, "The One," which treated Obama mockingly as a self-styled messiah.

John Geer, a political science professor at Vanderbilt University and political advertising expert, said "The One" is a good illustration of the difference between TV and online spots. "Web ads are going to be pushing the envelope a little more than regular TV ads," Geer said. "You can take more risks and gambles with them. They're a little more tongue-in-cheek."

While online videos usually face less scrutiny from the press than traditional paid media advertising, there are still limits on how far they can go. One McCain Web ad, "Lipstick," generated controversy by taking commentary from CBS anchor Katie Couric out of context to imply that Obama was being sexist toward Sarah Palin. CBS, citing copyright issues, requested it be removed from YouTube -- but only after thousands had already watched it.

Despite the risks, campaigns often conclude that releasing edgier and more divisive ads online is worth it for the free media coverage they can generate. "Web ads are the new press release," All said. "The majority of them are targeted at bloggers and the news media. By creating a quote-unquote Web ad" about a particular issue, campaigns are able to raise "the specter of that issue a degree or two above what a press release would do."

Evan Tracey, head of TNS Media Intelligence/Campaign Media Analysis Group, a firm that tracks political advertising, said he doubts the influence that online videos -- especially the more outlandish ones -- are having on undecided voters, since such people are unlikely to seek them out. Instead, he said, undecideds see these videos through media coverage. "The campaigns are helping us fill the 24-hour news cycle," Tracey said. "At least we know these ads are going somewhere."

In addition to official campaign videos released to the Web, this election year has also seen the emergence of user-generated content, which Grove described as an "even more interesting phenomenon than candidate-generated [videos] because they're much more organic and can take on a life of their own." He cited as an example the support generated for Obama from the "Yes We Can" music video by Black Eyed Peas member Will.i.am. The video, which sets to music the speech Obama gave after his loss in the New Hampshire primary, has been viewed well over 10 million times on YouTube and -- although it was produced independently of the Obama campaign -- was quickly taken up by the Democrat at campaign rallies.

The "Yes We Can" video "took something that came from the campaign and added a creative user-generated flair to it," Grove said. "That's a dream come true for a campaign. To have someone hear [a] message, get what it's about and recommunicate in a way that's unique to that person is the best word-of-mouth advertising you could ever have."

Joe Trippi, an Internet consultant and longtime Democratic strategist, echoed Grove's thoughts on the campaigns' use of online video. Obama is "not as dependent on Web ads as McCain," Trippi said. "If you're farther behind online in terms of people creating their own Web content on your behalf, then you have to [produce] more Web ads and you have to be a little more creative."

Trippi, who has been working on Democratic presidential campaigns since 1980, couldn't stress enough the effect he says online political content -- everything from voter-generated videos to candidate speeches posted on YouTube to official campaign Web ads -- will have come November: "This will be the first election where that's what influences the outcome," he said.