Mr. Estreich and other members shrug off the notion that the group, which he described to the party blog as a “traveling Soho House meets 740 Park Avenue,” is just another private club (albeit, one without walls) for idle Upper East Side trust-fund kids. They see it as an online-and-offline professional networking club for well-born insiders who would find the typical networking event (not to mention, Facebook) a little mass.

Think of it as LinkedIn for the Bridgehampton polo set. If you’re lucky enough to have been born on third base, the Native Society has arisen to help you get home. “It’s not about who you were born, or what you were given, but what you’ve made of yourself,” explained one member, Alexa Winner, a 22-year-old stylist and fashion designer. “Anyone can come from a wealthy family, but it takes actual brains and ambition to do something with that.”

Native sensibility. Native mind-set. Those terms were tossed around at the Plaza gathering. Like Zen monks marinating on the essence of nothingness, members tried to put their finger on that ineffable quality that makes them worthy of membership.

To Anne de la Mothe Karoubi, 24, who went to the Marymount School, it’s an intellectual precociousness. “When you grow up in New York City, our minds develop faster,” she said. “You’re not from Wisconsin, you’re not from the middle of America. We’re international, we’re focused, we’re driven.”

To David T. Libertson, 23, an art dealer and consultant who attended Dalton, it’s a clubby familiarity. “You go on LinkedIn, you see one degree of separation, two degrees, three degrees, then it’s just all your other connections,” he said. “I can literally say I know everyone in this room through one other person.”