During the Internet's go-go days in the late 1990s, I thought the term generalist meant “she’s doing two jobs and pays herself double." Now it seems the word generalist means “good at nothing and unemployed." In either case, generalist is the label for a career that will die.

Think cars: You never hear an advertiser say, “Buy my car, it’s good for everything!" Volvos are safe. BMWs are fun. Saturns are easy to buy. Just as successfully branded products offer specific benefits, successfully branded careerists offer specific talents. You get to the top by being the best, and you can’t be the best at everything.

Ezra Zuckerman, a professor at MIT's Sloan School of Management, agrees — and has the research to prove it. In his study of typecasting in Hollywood entitled "Robust Identities or Nonentities," Zuckerman found that specialization leads to longer, more productive careers. Contrary to conventional Hollywood wisdom, big bucks come most often to people who become known for a certain type of role. Zuckerman finds that typecasting, as this practice is called, is also a moneymaker in the business world, where the hiring system is set up to reward those who differentiate themselves. "Headhunters are specialized," he says, "and they look for something they can package and sell."

Generalist is a good moniker during the first few years of your career. For example, if you’re a standout college grad, you may win a place in a general-management rotational training program, such as General Electric Co. and other well-known consumer products companies offer. But the point of such training programs is to figure out what you’re good at and then seek an internal role in that department.

So take a gamble. Figure out what you’re best at and start making your mark. Then hope for good timing — that someone needs that particular talent when you have become expert at it.

Carly Fiorina, for example, is an outstanding marketer in the technology sector. She got to be chair and chief executive officer of Hewlett-Packard by being the best — and having a little luck: the company badly needed marketing expertise when it was conducting a search for a CEO. If it had needed an engineering genius, Fiorina would not have been considered. By the same token, if a food-products company needed a marketing-oriented CEO, Fiorina would not have been a candidate because her background is in technology. People who define themselves clearly are clearly wrong for certain positions, but super-achievers take that risk.

Many professionals hesitate to define themselves because it limits where you can go. But top players must have clear definition. Most have enough confidence in their abilities to risk specialization. Very simply, they believe that adequate opportunities will be available as they progress up the ladder.

To specialize, think discipline (marketing, sales, operations, etc) and sector (media, technology, fashion, etc.) Become known for your extremes. If you aren't extremely good at something, you won't get to the top.

Still not convinced of the benefits of typecasting? Then consider the current job market. Hundreds of applicants vie for most jobs, and many are more than qualified. This means hiring managers can demand a perfect fit – and specialists rather than generalists typically offer a perfect fit.

Figure out what your strengths are and hone them. Sure, take varied positions in the company, and learn a range of skills, but make sure people know where your talents lie. People at the top need to see you as someone who is extremely good at something, and no one is extremely good at everything, so don't sell yourself that way to upper management.