This week, Quiznos gave away a million subs in three days after using only banner ads, Facebook and Twitter presence and some free local radio exposure.

Denny's may have been investing in brand awareness, but as the Quiznos promotion demonstrated, with consumers looking to save every penny they can, you probably don't need the Super Bowl part to drive a freebie.

Another current example of using a giveaway and online chatter to drive restaurant traffic: International House of Pancakes just completed its third annual National Pancake Day on Tuesday, in which it gives away a small stack of pancakes and in return asks customers to consider donating to the Children's Miracle Network or a local charity.

IHOP, which has raised nearly $2 million for charities since starting the day in 2006, relied on a dedicated Web site with a "tell a friend" pass-along application, its normal presence on key social networks and some PR to drive awareness and traffic.

The result? IHOP has not finished tallying, but the chain was shooting for $1 million and believes that this year was its best in terms of awareness, traffic and donations, according to spokesperson Patrick Lenow. "The word-of-mouth generated through social networks was just incredible," he says.

And that's just this month's roster of freebie-based promotions designed to draw in new diners, get existing customers to visit more frequently and pick up some revenue from the beverages and other purchases that usually accompany the freebie.

Social networking and restaurants are a logical match, says Reggie Bradford, CEO of social media marketing consultancy Vitrue. "Food is naturally social," he points out. "Where do you want to eat? Do you want to grab something here? This is translating to online conversations around restaurant brands. We've seen tremendous adoption of social media strategies among QSRs and fast-casual restaurants."

Combine social media with freebies, and you've got marketing dynamite. "Giving away food in these uncertain economic times obviously resonates strongly with consumers," Bradford says. "Huge gains are being made by brands who are reaching out to consumers with something tangible. IHOP deserves kudos for taking it important steps further by giving back to the community and forging loyalty along the way."

The lift in online buzz has been significant for all of these promotions, based on Vitrue's Social Media Index, which measures online conversations about a brand in social networks, blogs and Twitter.

Denny's SMI score more than doubled (from 22 to 45.6) after its commercial and meal giveaway. Quiznos' jumped from 12.4 on the first day of the promotion to 16.1 three days later, or by 30%. IHOP's score was 36.9 on Jan. 1 and 73.9 on Feb. 25, the day after Pancake Day--a 99% gain. Bradford recommends maximizing buzz by leveraging all of the potential touchpoints. For instance, he points out, the WOM for IHOP's event was largely organic rather than IHOP-driven, presumably because of the event's charitable mission. "IHOP has a formal Facebook page and more than 27,000 fans, but there was no call-out of the Pancake Day event on the page," he notes. "There were about 135 different events created around Pancake Day, but it looks like none were created by IHOP or connected with the Facebook page. They were created by Facebook users and some IHOP franchisees, and so lacked a cohesive or core message. I only learned about this event because I noticed that three friends had RSVP-ed to attend."

IHOP and other brands could benefit from more compelling Facebook pages, perhaps incorporating surveys, polling and a restaurant locator, Bradford says. Providing franchisees with the tools to tap their online social circles to market local events is another opportunity, as is capturing event RSVPs to go back to individuals with coupons and other loyalty-building offers, he adds.

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