Viewership of the Super Bowl is practically a given. Nielsen last year reported 111.3 million tuned in to watch the New York Giants spoil it for the New England Patriots again. That number was good enough to beat the 2011 Super Bowl, which pulled in 111 million. With this year’s matchup, pitting Harbaugh brother against Harbaugh brother, there’s not much reason to expect that number to go anywhere but up again this year.

Some will come for the ads. Ad Age reports that CBS has nearly sold out its ad slots for its Feb. 3 broadcast of the Super Bowl, with buyers saying that 30 seconds is going for an average of $3.75 million.

Some will come for the Halftime Show, for which sponsor Pepsi has brought in Beyonce. And some will even show up to see some football.

But before the first notes of the “National Anthem” start bouncing off the rafters of Mercedez-Benz Superdome in New Orleans, a number of advertisers will have spent weeks online drumming up interest in the games through crowd-sourcing.

“Crowd-sourcing can be really good for large brands,” said Corey Christiansen, social media strategist at Metia, referring to Doritos. “It’s actually very cost effective for them to put something out there where they can have people submit and then they get a lot more earned media before and after the game.”

Doritos again ran its “Crash the Super Bowl” campaign online, in which it gets fans to vote via Facebook for consumer-submitted spots. Doritos will give one of its two 30-second spots this year to the winner—the current leader features a goat unleashing a peculiarly human scream—and the other will go to a submission of the company’s choice. “Crash the Super Bowl” is entering its seventh year and the results have been remarkable. Ad tracking company AceMetrix awarded the Cool Ranch company the highest AceScore—which measures consumer impact—among all ads aired during both the 2011 and 2012 Super Bowls.

Christiansen noted that the online voting aspect of the campaign lent itself well to mobile traffic. Similarly, Audi let fans vote through its YouTube channel to pick the ending of its Super Bowl spot. Ford Motors, through its efforts to rebrand Lincoln, launched a campaign with help from Jimmy Fallon, to collect weird road trip stories via Twitter and use five of them in the brand’s Super Bowl ad.

Crowd-sourcing can obviously be done over any internet connection, but going through mobile-optimized social media platforms like Facebook, YouTube and Twitter increases the chances participants will vote and contribute using a mobile device. Considering the success of Instagram alone as an indicator of the popularity of mobile photo sharing, Pepsi’s online campaign to crowd-source the Halftime Show likely drove plenty of mobile traffic. 

“Pepsi has already had 80,000 people send in photos,” Christiansen said. “I think that’s a huge success for them even before the game.”

Pepsi invited fans to submit photos (the deadline was Jan. 21), via the company’s web and mobile sites, of them engaging in activities ranging from tapping their feet to throwing confetti, with the promise that some would be used in the show’s introduction.

Whether directly or indirectly all this pre-game promotion will undoubtedly drive some mobile interaction with the Super Bowl well before the opening kick-off.

While Jeff Hasen, chief marketing officer at Hipcricket, sees the value these crowd-sourcing techniques will create with mobile interactions before the game, he’s keeping his eye on game day and days following.

“I think that crowd-sourcing is good because it builds excitement and anticipation for the spots,” Hasen said. “But to me, from a mobile perspective, it’s not so much the before as it’s the during and the after.”

“When it comes to the Super Bowl, what you’re looking to do is to attract as many people as possible. Some of the inclusive mobile products and services are the ones that are going to have the ability to get the Tuesday and Wednesday interactions with the viewer.”

Beyond the watercooler discussion Monday and extended interaction through platforms like USA Today’s Ad Meter, the democratic efforts of brands like Doritos and Audi won’t live past the voting deadline either online or through mobile since the crowd’s participation essentially ends once a winner is chosen. But crowd-sourcing approaches like Pepsi’s and Lincoln’s appear to have more sustainability that could transfer to any brand and provide interaction, some of it mobile, with consumers without the need for tying in with a big TV event like the Super Bowl.