GONE ARE THE DAYS when every fresh graduate's ideal career track involved rising through the ranks of a Fortune 500 company. Budding start-ups are shaking up the job market across the country -- most notably in the high-tech world, where Internet start-ups are sprouting up like weeds in an already tight job market.

As a result, many large, established companies are not seeing the influx of recent graduates they are used to: 27 percent of the Harvard Business School class of 1999 accepted jobs at companies with fewer than 100 employees. And some longtime employees who did move up the ranks the traditional way are heading out into uncharted territory just as quickly.

"This is really the first time that technology and business have blended so well. It has changed the way companies can get started, with a lot less capital and with models and technologies still being figured out," says Rob Miller, president of StartupNetwork.com, a Boston-based job-placement site for start-up companies and their potential employees. "The Net is a totally new wave of innovation, and people just want to be involved in it."

Start-ups have a lot to offer: the excitement of being part of a huge trend, the chance to possibly help create the next big business success, attractive stock options and other financial rewards, and more.

Equally appealing to those who seek varied experiences and opportunities is the culture of a small company.

"I went to high school in the '80s when, from my point of view, the ultimate career would be to work your way to the top of IBM," says Anne Hale, a business systems analyst at Cardiff Software, in San Diego. "After graduating college and joining a large firm, you are immediately aware of how far away the top is, as well as the levels and politics that need to be navigated in order to move. The amount and variety of involvement in various aspects of the business that you have in a small company far outweigh, in my opinion, some of the trade-offs."

All of these factors are fueling the start-up fire and pulling many technical professionals onboard.

"IT professionals are finding that their skills are in demand everywhere," says Gale Sroelov, vice president and human resources consultant at A&S Computer, in Union City, Calif., who works with many start-ups in the hiring and HR development phase. "They get the advancement in their careers without really trying very hard. And if a professional has an idea, they do not need to concern themselves with a [traditional] career path anymore -- they can find funding to start their own venture and do it themselves."

However, working for start-ups is not for the risk-averse. Those considering making the leap should weigh the potential payoff, in both money and experience, against the high stress and few guarantees that come with start-up work. And they should remember that a start-up may not be the only place to gain entrepreneurial experience.

Riding the wave of change

Several economic and technological factors are driving the current momentum behind start-ups: a healthy overall economy, the explosion of the Internet, and new business opportunities created by these changes.

"Everybody wants to make a killing, and the Internet is fueling it," Sroelov says. "Someone will have an idea, and there is an investor out there who will fund it. The good news is that anyone can and has been able to create and fulfill that American dream."

Technology itself has also moved to the forefront of our economy as high-tech companies drive the stock markets and corporate CEOs place more emphasis on the technology plans of their companies.

"As our economy has shifted to one that prioritizes information services, people with new ideas have become more powerful, and businesses based on new types of information-technology services have a wide-open market," says Elizabeth Falk, a career consultant at Odyssey Consulting, in Arlington, Mass. "The money is out there right now, so the risk to start-up businesses is relatively low. On top of that, a good technology professional can be involved with a 'failed' start-up and still remain respectable because he or she has demonstrated some creativity and initiative."

Because of this phenomenon, start-ups are starting to carry a higher profile as part of the ambitious person's career path. In the past, working somewhere new and small wasn't always taken seriously. Now, many of the negative factors associated with start-up experience, such as short time periods in positions, control over small budgets and staffs, and unproven success tracks, are often overlooked.

"While start-ups would once have been considered risky ventures, it's a much more common part of a career path today," says Jana Rich, principal at Korn/Ferry International, in San Francisco. "It also means that people are staying in jobs for shorter periods; it's more acceptable to have shorter stints on a resume while the person tries out a start-up venture that might not always be successful."

Because of these changes, more and more high-tech professionals are seeking start-up positions. The registered visitors' list on Miller's StartupNetwork.com site is approaching 3,000, with about 300 start-up companies posting current openings.

A Harvard Business School graduate who helped form the school's Cyberposium, an event that brings graduate students together with international business and technology leaders, Miller personally identifies with the lure of start-ups for those who use his site.

"Being involved in all of that excitement is the lure; that's what brought me into it," Miller says. "How do you use the [Internet]? How do you make money with it? It's about not wanting to miss a bandwagon."

Karen Barnes, vice president of engineering at Resonate, in Sunnyvale, Calif., has been attracted to start-ups because of the entrepreneurial draw and the chance to see her work make a difference.

"After going into a smaller environment and a challenging experience, the idea of going back to something huge sounds very boring," Barnes says. "The company is growing by leaps and bounds -- it's so fun and there's so much to learn."

Not all greener pastures

But Barnes and others warn starry-eyed start-up seekers to consider carefully what they're looking for before they make the leap. How will they react to a constantly evolving environment? Do they depend on getting a paycheck each week?

"It always amazes me how many people in [Silicon] Valley are more interested in money," Barnes says. "They all think the next start-up will be the thing that helps them retire, rather than 'Will this benefit my career?' But what's the percentage of start-ups that really make it?"

Miller adds that, although the stock options and other projected financial goals sound attractive, there may be other not-so-shiny financial aspects of start-up work. For instance, working for a reduced salary or no salary for a short time is not uncommon at early-stage start-ups. For this reason, StartupNetwork.com asks screening questions designed to give site visitors a start-up reality check.

"For companies in an idea stage, you are going to go without a paycheck," Miller says. "And if that's something you can't do, then you have to consider that when looking at what stage of start-up you will go to, with what amount of funding."

In addition to assessing your ability to manage financial risk, you must also consider the often nebulous nature of start-ups and how that will affect the environment and type of work you do. Many start-ups change direction, product, and purpose several times before being ready for prime time, and that means the nature of your position can evolve several times as well.

"Many people aren't prepared for the commitment they need to make to a new company in order for it to succeed," Odyssey's Falk says. "The more realistic -- and mature -- professionals are most likely attracted to start-ups because of the opportunities for autonomy and creativity, two things that most of my clients say are high priorities."

Sroelov adds that having a personality and work style that match the start-up pace are key to succeeding on this track.

"The individual has to have a certain personality to make it in a start-up," Sroelov says. "If someone has been in large companies their entire career, they are not going to be able to cut it in a start-up. What I've seen is most small start-ups shy away from the big-firm career people. If someone does step into the fire, they will know pretty quickly if they can cut it. Kidding yourself doesn't work, because there is no place to hide inside a start-up."

Entrepreneurial experience

The good news for those ambitious high-tech professionals who aren't quite ready for the leap into a start-up is that many start-up qualities can be found in large, established companies as well. Particularly as the job market has tightened, more traditional companies have found ways to improve their tangible and intangible benefits to attract and keep good employees, industry observers say.

"This is more true today than ever, as larger companies create new divisions focused on the electronic-commerce world or spin out parts of their companies -- both to capture economic value [and] as a retention tool to keep their people from leaving to go to the dot-com world," Korn/Ferry's Rich says.

And experts say that missing out on the start-up experience won't hinder your career growth if you are on track at your current company.

"Someone has to be on hand to implement the ideas and the technology developed by start-ups, and there's plenty of opportunity to learn and grow with an established company," Falk says.

Monica Nester, senior vice president of marketing at Annuncio Software, in Los Altos, Calif., says that although she is at a start-up now entrepreneurial aspects of her previous positions at large companies provided her with the variety and challenge she was seeking.

"There's a whole different entrepreneurial experience taking place out there, so no matter what you're doing, any involvement that touches the Internet gives you an entrepreneurial experience in a sense," Nester says.

However, seeking out entrepreneurial experiences in large companies doesn't always translate into a start-up experience, Falk warns.

"I don't think there are many truly entrepreneurial opportunities that come from within large companies," Falk says.

And people who work for successful start-ups -- those that grow into big companies -- may see fewer entrepreneurial opportunities as the company grows.

"Certainly, it's possible to stay with a start-up as it grows larger, but that means sticking with a project through some significant changes and challenges," according to Falk.

For this reason, those who are truly built for the start-up lifestyle will often continue to seek out start-up environments after their own company has reached a particular level of growth or success and is no longer changing at a ferocious pace.

"Most people who enjoy the start-up mode usually lose interest after a company has grown," Sroelov says. "Their roles will change from hands-on to more of a management capacity, and the true hands-on professional will want to have the more isolated 'work-til-you-drop' environment from the early start-up."

However, for those who seek the thrill of the start-up, the current pace of business growth and change seems sustainable. All signs point to room for new start-ups to flourish even as start-ups of the recent past consolidate and become larger companies -- or fade into the background.

"I don't really see any decline in venture investing in the short term," Rich says. "As business-to-business electronic-commerce continues to grow, we will still experience very strong rates of new companies being funded."

And the entrepreneurial fuel that has helped spark the start-up wave is not in short supply.

"The lure of the start-up is always going to be there," Miller says. "People get addicted to entrepreneurship."