More than salary, position, culture or any other factor, there is one thing that Millennials want from employers: a sense of purpose. Levo co-founder and CEO Caroline Ghosn asked an audience at the Fortune Brainstorm Tech conference not to roll their eyes in skepticism when she explained that Levo’s surveys and focus groups indicate that 84% of 18- to 34-year-olds—defined as Millennials, or Gen Y—rank “purpose” supreme in evaluating whether they are in the right job and want to stay there.

Tuesday afternoon’s Brainstorm Tech session, titled “The World According to Gen Y,” explored the challenges and opportunities in hiring and retaining Millennials, who today make up the largest segment of America’s workforce. While Gen Y is not yet dominating Europe and Asia, there are 2.5 billion in this cohort across the globe. Not only are Millennials the most connected generation that the world has ever seen, they are also the most commonly cosmopolitan. “Twenty-four-year-olds who grew up in Tehran, San Francisco, and Rio de Janeiro all grew up with Reddit, Tumblr, Instagram, Facebook FB and Twitter TWTR ,” said Chris Altchek, the CEO of Mic, a news service tailored for Gen Y.

Altchek, 27, said that Gen Y also has a greater divide between rich and poor than any previous generation—and its own kind of social consciousness that derives from that.

Millennials value authenticity, transparency, and democratic access. (“Not that President Obama will tweet at me, but I can tweet at him,” notes Ghosn, 28, who co-founded Levo, the professional network for Millennials.) They’re also more restless than the Gen X-ers or baby boomers who came before them, so the onus is on employers to woo them by communicating authentically, transparently, and with a respect for Gen Y aversion to authority.

Clara Shih, the 33-year-old CEO of Hearsay Social, suggested that companies should think of an employer-employee relationship as “an alliance”—a term that venture capitalist and LinkedIn LNKD co-founder Reid Hoffman describes in The Alliance, his 2014 book on managing talent in the networked age. “You’re agreeing that this is what the company will give, and that this is what the employee will give back,” says Shih. A job, in this iteration, is like “a two- or three-year tour of duty.”

While social networks unite Millennial values across continents, companies still have to cater to cultural differences, said Shih, who is on the board of Starbucks SBUX . When Starbucks CEO Howard Schultz realized that parents and families in China are very involved in their adult children’s career choices, she explained, he decided to host a “parent forum” in Beijing, meeting with parents and grandparents of his in-store baristas. “This wasn’t just reaching out to the employees, but to their influencers as well,” she said.

The need to cater to Millennial values—and that sense of “purpose”—will only increase for employers as Gen Y matures. Millennials are expected to comprise 75% of the global workforce by 2025. “We’re only going to get stronger,” Ghosn says.