You’ve probably heard people talk about checking in on Foursquare. If you’re a business owner or knows someone who owns a business and you’re not using Foursquare, you’re missing a big opportunity.

Foursquare is a location-based social networking app and website for mobile devices that allows you to keep up with what your friends are doing, discover and rediscover what’s nearby and unlock deals. Foursquare users, often called players, do this by checking into a venue when they arrive and competing for the mayorship, which is the person who checks in most often over a set period of time.

Businesses can, if they choose, offer discounts and deals to people who check in, people who become mayor or both.

Here’s an example. Say you own Smith’s Soup and Sandwiches on South Second Street. You can use Foursquare to entice customers to check in and compete for the chance to unlock discounts. You could offer a customer who checks in 10 percent off their bill and provide something bigger – like a free grilled cheese sandwich – to the mayor. (Side note: If you own a sandwich shop and don’t have grilled cheese on the menu, you should strongly consider adding one).

Why would you want to be a part of the Foursquare craze? Simple. According to the company, nearly 15 million people use Foursquare worldwide. More than 1.5 billion check-ins have been recorded since the network launched in 2009, and millions check in every day. Plus, more than 750,000 merchants have claimed their venue – the page customers go to check in, interact and claim discounts and prizes.

Back to the grilled cheese for a second. If my friend is mayor gets a grilled cheese sandwich just for using Foursquare, he’s likely to tell his Foursquare-playing friends and so on. It’s word-of-mouth combined with gaming that sells itself. That’s why businesses can and should be creative with the kinds of discounts and deals they offer. The more they stand out, the more they’ll be talked about.

Foursquare offers a free set of tools to help businesses and brands best utilize the platform for their needs. If you’re not ready to jump in, I recommend finding a similar business or competitor using Foursquare and see how it uses it. That might just open your eyes.