The fanfare, inflated stock prices and overnight paper fortunes that surround the Internet's manic incursion into American life have obscured an important shift: The industry is graduating from a speculative casino into a measurable force that is changing nearly every corner of modern capitalism.

The Internet is rapidly slashing costs between suppliers and companies, and between companies and customers. As it creates entirely new businesses and realigns old ones, it is scrambling notions of corporate value, giving birth to a new business math that remains volatile but increasingly draws from real numbers about sales, productivity and even profits.

The precise impact of the Internet is still hard to quantify. One reason is its sheer rate of growth: Every second, another seven people around the globe tap in for the first time. But enough data has begun to emerge -- and several companies have established enough of a track record -- that the glimmerings of a new business era are becoming visible, one that should endure through eventual recessions.

Earlier this month, after perhaps the most comprehensive study undertaken on the subject, funded by network equipment maker Cisco Systems Inc., researchers at the University of Texas said the Internet generated about $301 billion in U.S. revenue in 1998 -- closing in on the automobile industry.

Business-to-business commerce alone is likely to swell thirty-fold, from $48 billion last year to $1.3 trillion in 2003, according to technology consulting firm Forrester Research Inc. Forrester estimates that consumers spent $8 billion buying computers, books, CDs, clothing and other items on the Internet last year.

The impact is increasingly measurable at the company level, too. Boeing Co. says it has saved hundreds of millions of dollars by moving its cumbersome system of spare parts sales and technical aircraft maintenance manuals to the Internet. Airlines have reduced the cost of processing a ticket from $8 to $1 by discarding paper copies for electronic tickets, or e-tickets. And McLean entrepreneur Frank Borges LLosa, 24, took an idea for a nifty way to eliminate floppy disks using the Internet and, five months after creating his own company, sold it for almost $1.7 million.

One astonishing aspect of all this is that only five years ago, the Internet was essentially a fringe tool, the province of selected government officials, university researchers and geeky hobbyists. Executives mostly ignored it, and some called it a fad; politicians never mentioned the medium, let alone took credit for it. Few declared it revolutionary.

In fact, the speed of change is what has made it so difficult to place a value on Internet companies, their stocks or their technological achievements. For instance, when big Internet companies acquire smaller ones, a key component of the purchase price often is how many days of development the acquirer will save by buying the target's technology rather than trying to develop it independently. Compared with industries where markets are growing more slowly, the value of "Internet time" is enormous -- to a company waiting to sell on the Internet, days are worth months of ordinary business time, and months are worth years.

Lanny Baker, an electronic media analyst at Salomon Smith Barney Inc., said he can make a rational case for some of the sky-high valuations investors have placed on what are now called "blue-chip" Internet companies.

Baker notes that on average, media companies earn about $5 per subscriber (at the high end, major newspapers can generate about $128 per subscriber, he says). America Online Inc. earned a respectable $8 per customer in profit last year -- but is likely to earn $45 per subscriber this year.

Meanwhile, the online population continues to climb. Currently, about 80 million Americans are online, according to the Commerce Department. In 3 1/2 years, Baker predicts, that number will grow by about 60 percent to about 130 million -- or half of the nation's population. Both the potential for new customers and the possibility that AOL could earn as much per subscriber as a successful newspaper justify AOL's lofty stock price, Baker said.

As of Friday, the market value of AOL's stock -- $114 billion -- was bigger than the value of Time Warner Inc., Times Mirror Corp., the New York Times Co. and The Washington Post Co. combined.

Net.Capitol Inc., a three-year-old Internet software firm that crams all 18 of its employees and a dog into a rented Capitol Hill town house, recently went through a similar valuation exercise.

Net.Capitol develops software for political groups. With just 150 customers, it is a small business by any traditional measure -- except that traditional measures don't apply in this new world. Last month a potential buyer materialized and offered a stock deal that is potentially worth $12 million to $15 million.

Net.Capitol's assets -- a handful of employees, its software and a collection of computing hardware -- would struggle to bring even $1 million by objective standards. But "real world notions of value are just not relevant here," said Oron Strauss, the com pany's 26-year-old founder and majority shareholder.

When Strauss sat down to negotiate with Net.Capitol's suitor -- a soon-to-be-public company based in the western United States whom he declined to name -- they had to consider a whole new set of factors. What is the value of the "Internet time" it takes to build an online brand? How much is an Internet employee worth? How big might the political market be if every campaign uses the Internet?

But despite emerging hints of a science to the valuation, economist Lester Thurow, who sits on the board of online stock brokerage E-Trade Group Inc., concedes that he has come up with no comfortable way to value Internet stocks. He attributes the lofty valuation of some Internet stocks -- greater than that of many of their brick-and-mortar competitors -- to a simple game of chance. "I think it's the lottery model," he said. "Americans buy millions of lottery tickets knowing they're going to lose money." But one in a million wins big -- and that keeps everyone buying.

Low Costs, High Revenues

The Internet's impact can be much more clearly quantified in businesses and industries, which have seized upon the World Wide Web's speed and accessibility to reshape many basic operations. The airplane, a creation of the Industrial Age whose use and manufacture is among the most labor-intensive and costly of any product, offers a glimpse of how the network can create big efficiencies.

A quarter-century ago, there was an airline ticket office on many downtown street corners in the nation's big cities. Then the airlines gradually withdrew from the retailing of tickets, passing the job off to travel agents whom they paid 10 percent or so to process tickets. Lower-paid agents replaced the airlines' often unionized agents.

Now, it is the travel agents who are being replaced, by the Internet, as airlines start their own direct-sell Web sites where travelers buy e-tic kets. The more adventurous airlines have even joined forces with the likes of Microsoft Corp. and online bazaar Priceline.com to sell seats to a wider audience of potential customers.

"Clearly the Internet is the low-cost method of distribution," said David Swierenga, chief economist for the Air Transport Association. "When you do the e-ticket, it's the customer's computer talking to the airline's computer. No people involved."

The cost of processing a ticket online is estimated by the industry at about $1. That can be as much as 85 percent cheaper than using an agent or some hybrid of agent and computer reservations system, he said.

But the Internet can do more than lower costs. It can also raise revenues. It is allowing airlines to fill seats that otherwise would be empty when the plane takes off. Every day, airlines have as many as half a million empty seats available.

In 1996, American Airlines began offering unused seats at sharp discounts to frequent fliers who chose to receive weekly fare offers by electronic mail. The service began with 20,000 subscribers, but today the airline is sending out more than 2 million e-mails a week. One recent offer: a round-trip ticket from Reagan National to New York's JFK for $69.

Priceline.com has taken the concept even further. It allows would-be travelers to name prices they're willing to pay for airline tickets that would otherwise go unsold, then uses the Internet to communicate those bids to airlines such as Delta. "An airline like Delta in the past could not see the customer it wasn't getting," said Priceline.com Inc. founder Jay Walker. "It's kind of like an X-ray into the market. Only in the age of the Internet can you imagine a business like this."

And only in the world of the Internet can you imagine the economics between Priceline and Delta. When it was starting up, Priceline needed the airlines more than they needed it. So Priceline offered Delta a deal: Give us seats in exchange for rights to acquire Priceline stock once the company goes public. Today, Delta's stake is worth as much as $1.8 billion, more than Delta earned from its entire business last year.

The Internet is also reshaping aviation maintenance. Boeing, for example, is using it to sell aircraft parts to its airline customers and to share millions of pages of technical drawings and maintenance manuals with mechanics in the field. The Seattle plane maker says the Internet is helping it save "hundreds of millions of dollars" annually.

Last year, Boeing's online parts-distribution Web page handled 1.6 million transactions, more than double the volume of the prior year. The company also has an online system whereby airline mechanics can download technical drawings and maintenance manuals in minutes rather than relying on fax, telephone or mail for the information.

All this greatly speeds the pace at which planes are serviced, increasing the profitability of airlines as they minimize the amount of time that planes are out of commission.

Without the Internet, aircraft maintenance often requires mechanics to sift through thousands of documents and drawings on tiny cardboard cards with picture windows filled with microfilm-like images of parts until they find what they need. Sometimes, mechanics have to fly between airports to bring parts or technical drawings to a waiting plane.

Boeing Senior Manager Bill Shaproski recalls a recent event where a Cathay Pacific 747 sat idle in Tokyo while mechanics searched high and low for information on a damaged bracket that held an auxiliary power supply in place. Though not a life-threatening problem, it had to be fixed before the plane could fly again.

"They looked all over their drawing files, their aperture cards, millions of which are kept in a library," Shaproski said. "They couldn't find this card." Eventually, the specifications on the part were located, in a database at a Boeing supplier, and the bracket was replaced. But not before the flight was canceled.

With Boeing's new electronic parts and technical data system, though, situations such as the one in Tokyo should become a thing of the past. "Something that in the paper or microfilm world would take maybe five to 10 hours you can do in about five seconds," said Shaproski.

On a more mundane level, LLosa launched a simple notion last December: a "virtual floppy disk" service that spared personal computer users the nuisance of carrying disks around. Instead, they store data on a Web site and get it from there when they need it. LLosa employed just one full-time person (himself) at his NetFloppy.com LLC, and three part timers. He worked out of his basement in McLean.

Soon after NetFloppy started, online community Xoom.com took an interest in it. Negotiations ensued. Were his employees willing to move to California, How much was LLosa's idea worth? How about the five months of building a brand? In May, LLosa sold the basement outfit to Xoom.com Inc. for $1.65 million in cash and stock. His share: $1 million. Not bad for five months' work.

"We didn't even have time to print up NetFloppy business cards," said LLosa.

THE INTERNET GETS DOWN TO BUSINESS

While many leading Internet companies have yet to turn a profit despite soaring (if volatile) stock prices and huge market caps . . .

Amazon.com - Market cap: $18 billion

Lycos - Market cap: $3.8 billion

SOURCE: Bloomberg News

. . . the Internet economy now rivals that of standard industries, and its growth rate is expected to intensify . . .

Revenue generated by the Internet, in billions

1995: $5

1998: $301

1998 revenue, by industry, in billions

Energy: $223

Telecom: $270

Autos: $350

SOURCES: University of Texas, Commerce Department

Intercompany trade of hard goods over the Net

2003: $1.3 trillion

SOURCE: Projections from Forrester Research Inc.

. . . as increasing numbers of people become regular Internet users.

Number of Americans connected to the Net

1993: 3 million

1999: 80 million

Number of Web sites in use

1993: 26,000

1999: 5 million

Percent of U.S. adult population who are now regular Net users: 42.2%

Number of adults going online every month: 64.2 million

NOTE: Figures for intercompany trade are projections.

SOURCES: Commerce Department, MediaMark Research