By Patricia Sellers

Any Baby Boomer who has worked alongside Millennials — Gen Yers born after 1978 — knows how differently they view work and career. While we Baby Boomers typically place high value on pay, benefits, stability and prestige, Gen Y cares most about fun, innovation, social responsibility, and time off.

One person who has been thinking a lot lately about this generational divide is Shelly Lazarus, the chairman of ad giant Ogilvy & Mather WPPGY . That’s not just because her clients — such as American Express AXP , Ford F , Coca-Cola KO and Unilever UL — need to heed the attitudinal differences in order to craft their marketing strategies, but also because half of Ogilvy’s employees are under 30 years old. When I visited Lazarus a few days ago in her office, overlooking the Hudson River on Manhattan’s far west side, she told me that as she’s giving talks about Millenials, audiences are blown away by this one fact:

Sixteen is the number of months before an average mid-20s employees leaves a job.

Wow. What’s a manager to do to keep a Millenial on board? I — one of those classic Baby Boomers who has been at one company, Time Inc. TWX , for 26 years — can’t stop thinking that not only corporate loyalty but commitment to building a career may be a thing of the past.

There’s more evidence in today’s front-page story in the New York Times, “A New Generation, an Elusive American Dream.” While the article focuses on the horrible job market for today’s twenty-somethings, it suggests that these new adults are pretty much unfazed that they’re not launching into a dream career. Apart from 14% of young adults who are unemployed today, 23% are not even seeking work, according to the Bureau of Labor Statistics. The New York Times notes that the total, 37% of young adults unemployed or not seeking work, is the highest rate in more than three decades and reminiscent of the 1930s.

It makes you wonder: Will this emerging generation of leaders ever care as much as we did about building careers? And, if not, what does that mean for business?