A teaser for Volkswagen's ad has drawn more than 11 million viewers on YouTube. The campaign features a pack of dogs barking out a "Star Wars" song, repeating a theme from the company's well-received ad during last year's Super Bowl. (link.reuters.com/nuq46s)

That level of pre-game hits is "astonishing," according to Tim Calkins, marketing professor at Northwestern University's Kellogg School of Management.

"That would be a pretty good viewership for a primetime network television show," Calkins said.

Several other Super Bowl ads, or at least short teaser spots, have popped up online to try to grab attention before the New England Patriots and New York Giants kick off on Sunday.

More advertisers are encouraging their agencies to upload their ads to websites like YouTube and Vimeo to generate as much buzz as possible, especially as the cost of 30-second commercial spots have soared to average at $3.5 million this year.

Ads getting notice include a Honda Motor Co spot with Matthew Broderick playing off his iconic film role as Ferris Bueller. In the commercial, the actor calls in sick and spends a day cruising around town in a Honda CR-V. (link.reuters.com/muq46s)

Another commercial features comedian Jerry Seinfeld reuniting briefly with the Soup Nazi from his 1990s television show, in a pitch for Honda's Acura model. (link.reuters.com/puq46s)

Each of those spots were viewed more than 10 million times each within days of being uploaded on YouTube.

Automakers' spots are drawing the most pre-game interest online, according to the CNBC/Collective Interactive Super Sunday Ad Tracker, which follows discussions on social media, blogs and other sources.

On Friday, Honda was leading in "total buzz" with more than 75,000 mentions, followed by Volkswagen with more than 55,000 mentions.

Soda maker Coca-Cola, which is bringing back its Arctic polar bears, ranked first among non-car companies with more than 17,000 mentions. (link.reuters.com/quq46s)

For many advertisers, the pre-game attention will provide a big boost. But there is some risk to releasing ads in advance - if people have already heard about the ads and know the punchlines, they may use commercial breaks to grab a snack.

"If it's one of the top three or four (before the game), that's going to help it," said Charles Taylor, marketing professor at the Villanova School of Business.

For less popular spots, "you already know what's in the ad. There's not any suspense left," he said.

According to executives from Comcast Corp's NBC television network, broadcaster of the Super Bowl game, a 30-second commercial slot cost $3.5 million on average this year, up from $3 million for last year's Super Bowl, which was on News Corp's Fox station.

An expected 100 million people will watch the game, among a dwindling number of TV programs that still draw big live audiences.

The Super Bowl, including lower-priced halftime slots, could easily generate over a quarter of a billion dollars in ad sales.

Anheuser-Busch, which typically buys exclusivity as the only beer advertiser during recent Super Bowls, is again the biggest spender, according to industry sources.

Coke and PepsiCo Inc will face off for soda supremacy with campaigns that attempt to leverage social media after their commercials air.

"The Super Bowl has really gone from being a one-day advertising event to being a month-long extravaganza," Calkins said. "Many advertisers will be happy with their Super Bowl participation even before the game begins."

(Reporting By Lisa Richwine in Los Angeles and Yinka Adegoke in New York; Editing by Gary Hill)

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