(FORTUNE Magazine) – Next month, the current economic expansion will shatter records, lasting longer than any in history. It's easy to attribute this momentum to e-mania. The case is powerful and obvious: The Internet has increased productivity and connected far-flung economies, inextricably tying our well-being with Asia's and Europe's; unemployment is at a record low as dot-coms desperately throw cash and options at employees to retain and lure them; and investors are pumping absurd amounts of money into stock markets. As alluring and tidy as this explanation is, it's naive. In reality, a confluence of factors is shaping our growth. A change in any one of them could bring this dizzying run to an end. Here's a look at what's going on:

--Deregulation. The concept may sound so '70s (almost kitschy), but its effects have been key to increasing productivity and preventing price increases. Says Rosanne Cahn, chief U.S. economist with CSFB: "If it wasn't for deregulation, we would never have seen the spread of new technology today." In the past decade, policymakers have renewed efforts to inject greater competition into the economy by freeing up the financial, telecommunications, and utilities industries. It has paid off--prices have fallen and reduced operating costs for businesses. In addition, competition has forced firms to cut costs, trimming work forces and making remaining employees more productive.

--Globalization. The opening of new markets and competition from former Soviet bloc and emerging Eastern European economies--once readily dismissed--has forced U.S. manufacturers to slash prices, keep wages down, and increase productivity to earn a profit. In addition, the U.S. is more vulnerable to the whims of foreign investors than ever before. In the past decade foreign investors have doubled their holdings of U.S. Treasuries--they can now determine the fate of the dollar and interest rates. If they dumped their Treasuries, the dollar would fall--perhaps precipitously--meaning Fed Chairman Alan Greenspan would need to raise interest rates, which could spook the hell out of the market.

--Financial innovation. Now a far more important source of lending to corporate America than ever before, financial markets can offer cheaper alternatives to banks and other traditional thrift institutions. With the growth in securitized commercial and industrial loans, there are more opportunities for firms to raise funds. But it's a fragile, delicate arrangement, since more corporate and individual wealth is tied to the markets.

What it all adds up to is this: Our economy today is more open, competitive, and reliant on financial markets than it was 15 years ago. The interaction of all the factors is important to propel the expansion. For example, without cheap plentiful financial capital, many would not be in a position to invest in new technology. "If we lose sight of the other factors driving the economy and place too much faith in technology," says RFA Dismal Sciences chief economist Mark Zandi, "then we'll throw too many resources into the technology sector and expect it to solve everything."

Current thinking says that if you invest as much as possible in technology, the customer will come. Not quite--economists are starting to see things differently. If consumer confidence wilts, the benefits of deregulation are tapped out, the market drops, or foreign investors take their funds elsewhere, then the economy could melt. There are a hundred other factors that could go wrong too--things that technology can't offset. Keep that in mind next time you hear this expansion called the "Internet boom."

--Anna Bernasek