Founder and CEO Michael Waxman told CNBC that he was inspired to start the site when, after moving to New York, he grew frustrated with larger social media sites and wanted a different way to meet people.
Grouper's goal is to help you connect with strangers in the real world—the next evolution of social networking, according to Waxman. The company describes itself not as a dating site but as a social club.
"I think saying it's a date makes things uncomfortable," he said. "It really increases the pressure and people don't act like themselves."
(More Starters: Start-up creates New York's newest social network—for cabs)
Samantha Daniels, president of Samantha's Table Matchmaking, said that millennials' noncommittal nature has shaped the way they approach their offline social life, and Grouper is tapping into that shift.
Grouper said users also have made romantic connections through the more informal group gatherings.
"Most of the time, people want to meet people through friends—there's a comfort level," Daniels said. "The success rate may not be as high as a more traditional way of meeting someone. But like my grandmother says, 'If you're invited somewhere, you should always go.' You never know what's going to happen."
The dollars and cents of social dating
Grouper has deals with venues that include revenue for restaurants and bars, and secures tables for the group dates. The up-front payment structure also reduces the risk of being stood up and removes the awkwardness of deciding who will pick up the check.
The company declined to share precise revenue or profit numbers but said its business is improving.
Similar to other dating start-ups such as Tinder, Zoosk and Lulu, Grouper asks users to connect to their service via Facebook, where certain information is collected to help make matches in a "part-human, part-machine" process. This dual process, the company says, helps to maximizes compatibility.
Grouper is active in more than 20 U.S. cities, as well as Toronto, and plans to expand to Europe in the next six months.
(Related: The 12 best cities for online dating)
The Starters is a CNBC Web series that brings you behind the scenes of local tech start-ups. No matter where you live, a company in your city is trying to change your life. Follow us on Twitter
—By CNBC's Deborah Findling and Paul Toscano. Follow them on Twitter