Nicole Sullivan's job used to involve promoting the latest technology, so her résumé described her as an "evangelist." But after starting her own company, she needed to emphasize a different skill set.
Now, she likes to be known as a "ninja."
Ms. Sullivan isn't a black-hooded martial artist in Japan. She's a 32-year-old computer programmer in San Francisco who says she applies the sly skills of feudal Japanese warriors to writing software. "In the way you approach the code, you have a ton of tools available: throwing stars, knives, darts," says Ms. Sullivan, who founded Stubbornella Consulting in 2008. "The key is knowing which one will do some damage."
In Japanese folklore, ninjas were warriors who were skilled in espionage, traveled in disguise and often employed stealth fighting techniques many centuries ago. Today, a ninja is a hot new job title, vying to become the "guru" of the new century.
In 2009, the growth of "ninja" as a new job description far outpaced the growth of other trendy titles, according to LinkedIn Corp., a Web site that provides networking for more than 65 million professionals. While the numbers are still small on LinkedIn—some 800 current or former ninjas have public profiles on the site—their growth has skyrocketed past other fashionable careers such as "gurus" and "evangelists," says Monica Rogati, a scientist at LinkedIn who finds patterns in jobs data.
It's harder to quantify precisely what a ninja is.
"They're not coming from Japan," says Ms. Rogati, who first spotted the ascent of ninjas in 2003, but says they really took off last year. "They're just as likely to be software engineers or people with specialized skills working in the cubicle right next to you."
While most are computer programmers, the term has been used to describe expertise in everything from customer service to furniture movers. Jon Carlson sells the services of "ninja workers" in the Salt Lake City area. For $10 per hour per ninja, his team will do everything from housesitting to personal security to hauling junk.
Todd Bavol likes to be called the "Job Search Ninja," and published a book with that title last year that encourages people to use "creative skills from your bag of tricks" to find a job. "People who are doing the regular everyday things to find a job aren't being successful," says Mr. Bavol, the CEO of recruiting firm Integrity Staffing Solutions.
"The concept of a ninja is metaphorical. It's about confidence," says Alex Schliker, who has been advertising to hire one for his San Francisco business software start-up, CureCRM. It's "an easy way to say you need to be good at learning anything new I throw at you," he says.
Ninja is "sexier" than its predecessor, Mr. Schliker says: "Guru is so Web 1.0."
In finance, ninja has a more dubious meaning—it's an acronym for a kind of loan in which a bank hasn't verified an applicant's income, job, or assets. After the housing bubble, many of these sorts of loans ended up in default, with their borrowers disappearing like ninjas.
Valerie Frederickson, the CEO of an eponymous human resources firm in Silicon Valley, says ninja is just the latest in a string of unusual job titles for the tech industry that began in the 1990s with "evangelists."
"Technology was changing so quickly that companies needed somebody who could go out and convince customers to go with the new technology," she says.
But today's economy needs more employees who are willing to do a lot with a little. "Ninja panders either to the young or the young at heart. It is designed to make them work harder but feel good about it," says Ms. Frederickson.
The business world's love of vivid job titles dates back at least to "black belts," who first became popular in the 1980s thanks to the Six Sigma management strategy that uses the term. Management theorists spawned a generation of "gurus," although one of the most famous, the late Peter Drucker, once remarked that "we are using the word 'guru' only because 'charlatan' is too long to fit into a headline."
Bonobos Inc., a New York City start-up that makes and sells men's apparel online, has dubbed its customer-service employees ninjas. Its first customer-service representative happened to hold a fourth-degree black belt, CEO Andy Dunn says, which started the trend.
All of the ninja talk in the U.S. only sows confusion in Japan, where the term isn't used for jobs. Ninjas are mostly seen in TV period dramas and cartoons.
Jinichi Kawakami, honorary master of the Iga-ryu Ninja Museum in the city of Iga, is known as one of Japan's last living ninjas. He says that calling efficient workers ninjas is not completely inaccurate. But he's disappointed that the term has lost touch with its roots in the military arts. "As a Japanese person, I feel a bit of discomfort about it," says Mr. Kawakami, 60.
Ninjas aren't assassins, insists Mr. Kawakami, who trains by walking on his big toes. A real ninja must have stealth, intelligence, a righteous heart and patience, he says.
"Lacking any one of those, you cannot make a useful ninja. These things are required in the business world as well," he says.
The rise of ninjas in the tech world is being fueled in part by Amazon.com Inc., which hosts a ninja brain-teaser contest at job fairs and industry events when hiring computer-software writers. Winners get the title of Amazon Ninja Coder and a miniature foam statue of a sword-carrying ninja.
Ms. Frederickson, who says she has seen "enough ninjas to take a castle" recently, isn't convinced that becoming one is a good career move. "If you're going to give people funny titles, they should describe what the person does," she says. "What are you going to do after being a ninja—senior samurai?"—Miho Inada in Tokyo contributed to this article.