Of all the amazing changes the past three decades have brought, which were the most important? Four trends stand out as the entrepreneurial landscape's most transformative.

Technology
Travel back in a time machine to 1977, and you'd find few of the devices business people rely on today. Into the early 1980s, most personal computers were bulky things such as RadioShack's notorious TRS-80, known to users as the Trash 80.

As the '80s progressed, PCs and printers got cheaper and more reliable. Computer-processing power that had cost tens of thousands of dollars and taken up entire rooms could fit on an entrepreneur's kitchen table. Now a computer system could be had by any would-be business owner with a credit card or a sympathetic relative willing to lend some cash.

Programs such as 1977's VisiCalc spreadsheet software turned computers into more of a business tool. With the advent of Aldus PageMaker in the mid-'80s, computers became printing presses.

By 1982, the home computer was Time's "Machine of the Year." That year also saw the FCC authorize commercial cellular phone service.

From there, the revolution was in portability. By the late 1980s, lightweight laptop computers were hitting the road with executives and cell phones were starting to grow out of everyone's ears. It was easier than ever to launch a business from anywhere.

Also by the late 1980s, CompuServe and a few other early e-mail providers were saving savvy business owners on postage costs. Of course, the person you wanted to e-mail might or might not have an address yet.

The road to entrepreneurship had gotten cheaper and smoother. Only one thing could have made life better: the ability to tell the entire world about your company at very little cost, without ever leaving your desk.

The Internet
In 1993, the first widely used commercial browser, Mosaic, was released, and overnight, a little-known network linking the computers of a few university and government scientists became a tool for everyone. The World Wide Web was up and running.

While many big corporations slumbered, entrepreneurs were quick to launch companies that capitalized on this new way to reach customers. In 1995, both Amazon.com and eBay opened for business, and the e-commerce era had officially begun.

The rise of e-commerce was a boon to women and minorities, on the internet, nobody knows who you are, so their prejudices don't matter. There are very few barriers to web-based entrepreneurship. You can find a market for something like industrial music by selling to customers who like it, even though they're scattered all over the world.

That's basically what Greg Selkoe did in 2002 when he developed an online marketplace for the urban-street-fashions he liked to wear. Having watched other hip fashion sites disappear in the dotcom bust of 2000, Selkoe saw an opening and launched Boston-based Karmaloop.com. He scraped up $75,000 from family and friends to purchase inventory.

Selkoe, 32, now has 27 employees and expects 2007 sales to top $16 million--double last year's take. These days, up-and-coming designers pay for the privilege of being included on Karmaloop's Kazbah area, which showcases new underground brands.

Mary Cronin, a Boston College professor and author of the 1994 book Doing Business on the Internet, couldn't find a link to the book, so just italicize sees the explosive popularity of social networking sites such as Facebook and the increase in sophisticated mobile phones as two trends set to revolutionize e-commerce.

Globalization
In the 1970s, selling around the globe was mostly the province of large corporations. They had the bankroll to navigate the mysteries of other cultures, pay massive overseas phone bills and deal with complex import/export laws.

Even for the big guys, there wasn't as much of a globe to sell to. All of Eastern Europe was closed to U.S. business, and even Western Europe wasn't easily penetrated, says Andrew Bernard, senior associate director of the Center for International Business at Dartmouth College. A lot of Asia was closed off to Western trade, China was off the radar. India was restricted.

That would change dramatically over the next 20 years, as rounds of the General Agreement on Tariffs and Trade gradually removed trade barriers. In 1978, China began a slow trend toward openness to foreign companies. After the fall of the Berlin Wall in 1989 and the breakup of the Soviet Union in 1991, Eastern Europe was suddenly wide open.

As telecommunications became cheaper, barriers to foreign trade for small businesses were lessened, Bernard points out. As people and ideas began to flow more freely between borders, immigrants to the U.S. arrived with the know-how to trade with their countries of origin.

Individualism
For decades after World War II, most middle-class American workers snuggled in the bosoms of big companies that provided dependable jobs and pension security.

That all started to change in 1981, when President Ronald Reagan ordered the firing of 12,000 striking air-traffic controllers. Until then, says Blaine McCormick, associate dean at Baylor University's business school in Waco, Texas, mass layoffs were taboo.

But after Reagan's action, companies were emboldened to shed workers. After decades of a business climate, global competition was increasing and companies were facing challenges to operate more efficiently. Dozens of major corporations laid off employees at 10,000 a shot through the '80s. It was a deliberate and successful campaign to redistribute risks from companies to workers.

Laid-off workers often had severance packages that provided startup capital for new businesses. Millions more workers, though still employed, realized they couldn't depend on their employer for a lifetime. The age of the individual had begun. Workers began laying plans for their entry into the world of entrepreneurship.

That's exactly what Janis Dalessandro did, working on her sauce company on the side while she toiled for nine years at hair-care giant Paul Mitchell. A second-generation entrepreneur, Dalessandro, 43, never considered spending her entire career at a major corporation. - As I got older, I understood the beauty of creating your own path, she says.

- Research by: Wale Bello