Launched in 2009, Foursquare now boasts some 10 million users eager to let their friends know when they have "checked in" to a hip new store or favorite restaurant. Recently, the free service has rolled out a variety of services for businesses, including the ability to run specials designed to attract and retain customers.

The Company: Luke's Lobster, a chain of seafood restaurants with five locations in New York City and Washington, D.C.

The Goal: Reward loyal patrons

The Execution: Last summer, Luke's Lobster started using Foursquare to reward its "Mayors"—Foursquare lingo for the patrons who have checked in to a given location the most times in the past 60 days—with a 10 percent discount. But founder Luke Holden wanted to open up loyalty rewards to a larger group of customers. The grand opening of his chain's fifth location, in Manhattan's financial district, seemed like the perfect opportunity. Holden and Lauren Drell, the company's social-media and Web manager, logged on to Foursquare and created a Loyalty Special that would give repeat customers a chance to attend an exclusive launch party the day before the store's official opening in August. Customers who checked in to any Luke's Lobster location at least four times in two weeks unlocked the special, which instructed them to send an e-mail to luckyME@lukeslobster.com for more details and an invitation for two to the event.

The Result: By the end of the two-week period, 35 people had unlocked the special and e-mailed Luke's Lobster. Of those, 20 attended the launch party, where they mingled with members of the media and sampled lobster rolls, chowder, and wine passed around on trays. Holden and the store's management team chatted with the partygoers, who were asked to sign a guest book and indicate if they had landed an invitation through Foursquare. Throughout the evening, some guests commented about the party on Facebook and Twitter, which helped create buzz, Holden says.

The next day, the new location generated $7,000 in sales, double that of the company's last opening. Holden attributes some of that success to the launch party, which was the chain's first and cost only about $600. Overall, he was pleased with the Foursquare special, which helped him reward 20 loyal patrons. He plans to hold a similar event and Loyalty Special before the opening of his sixth location, next summer. Next time, he says, he plans to put more effort into marketing the special on Facebook and Twitter to boost participation. "I think it was a great success," he says, "but next time, we'll make it bigger."

The Price Tag: Free

Expert Tips

Cross Platforms
To maximize your reach, encourage customers taking part in Foursquare specials to post their check-ins on Twitter and include a hash tag, advises Rob Reed, founder and CEO of MomentFeed, a consulting firm in Santa Monica, California, that helps companies develop location-based marketing strategies. That way, you're spreading the word on two social networks at once.

Run Concurrent Specials
Instead of focusing on one type of Foursquare special at a time, Reed says, run multiple promotions simultaneously to see what works best for your business.

Check this out for more social media strategies.