(FORTUNE Magazine) – "Customers' power just keeps increasing," says William Stavropoulos, CEO of Dow Chemical. In Dow's industry, as in many others, they have taken heartless advantage of overcapacity, but customers' power is growing for noncyclical, structural reasons too. The most important factor: Customers know more than they did. Sometimes they share data formally, banding together to consolidate buying power.

Even in the absence of formal sharing, there are few secrets. Go to Yahoo, search "shopping" for Amanda Vaill's book Everybody Was So Young (a shameless plug for my wife's tale of Gerald and Sara Murphy, the preeminent couple among American expats in France in the 1920s), and in seconds you can compare price and availability at nine bookstores. Says Stavropoulos: "When information is almost perfect, you can't arbitrage it. The days when you could sell a product at one price in Germany and another in the U.S. are over."

In my last column (FORTUNE, April 12) we discussed how e-commerce changes distribution channels. The executive summary: totally. Many basic functions of distributors (aggregating information and inventory and assuming credit risk) are worth less in an e-commerce environment, so customers will want to bypass them, or at least not pay for them. The very nature of the Web--intricately hyperlinked so there's always more than one way to get from here to there--mocks the idea of channels, not to mention any hope of controlling them.

To survive in this Webbed world, companies need value-adding knowledge processes that compensate for the value and margin stripped from physical processes, processes that provide a way to reach and keep profitable customers. Knowledge processes fall into two broad categories: Some relate to knowledge creation, such as innovation or testing; others pertain to knowledge distribution, like sharing and protecting. The big one here is a customer-learning process--that is, a means by which companies learn about customers, customers learn about them, and companies and customers learn together.

Every company has mechanisms for getting information to and from customers. Advertising, market research, customer-satisfaction surveys, complaint letters, warranty claims--these have existed ever since God asked Adam why he chose the competition's product over His own and Adam replied, "Ask my wife. She does the shopping." But technology has a huge impact on the means by which buyers and sellers learn and on the economics involved. Says Robert Wayland, a Concord, Mass., consultant and co-author of The Customer Connection: "The basic process by which customers learn about companies and vice versa is the same, except that customers can search a lot faster and more cheaply, so their exit costs are dropping. The company response should be to pay more attention to the substantive pieces of the relationship." That means a shift of focus from selling to learning.

A fully developed customer-learning process will have four traits. First, it will emphasize communication over data mining. Without a process of mutual learning, there's little basis for customer loyalty in a low-friction knowledge economy. Second, customer learning must be integrated across business functions--not just confined to marketing, sales, and service but reaching into new-product development and even human resources. Third, the customer-learning process should be so visible day to day that you can't imagine running the company without it. Finally, and most important, the process should create "customer capital"--that is, buyer and seller should sense that their relationship is an asset to both of them, as real as any tangible asset. Both sides should be able to quantify the value of the relationship by measures like loyalty and transaction-cost savings.

No company I know of has a customer-learning process as thoroughgoing as that. But a lot are working on it. General Electric, for example, has adapted a practice that CEO Jack Welch admired at Wal-Mart and expanded it into an increasingly powerful customer-learning process. On a visit to Bentonville, Ark., back in 1991, Welch was blown away by Wal-Mart's Saturday-morning meetings, where two rivers of customer information came together: up-to-the-minute sales data and up-to-their-elbows reports from managers who had spent all week on the road visiting stores and soaking up impressions. GE, with next to no retail operations, transformed that into a technique it calls quick market intelligence (QMI)--insisting that all top managers regularly call on at least one customer, then holding regular meetings devoted to nothing but discussing what customers say and do. In typical GE style, the same setup is replicated in many places and at different scales. Cross-functional new-product development teams, for example, visit customers to discuss and test-drive ideas and feed what they learn both to R&D and to account managers. The emphasis: increasing the two-way talk with customers.

Health-care giant Kaiser Permanente, with 8.6 million members, is using the Web to create a multidirectional customer-learning process. At www.kponline.org, members can read medical encyclopedias, confidentially query a nurse or pharmacist, and participate in discussions on topics ranging from pregnancy to gerontology. These are moderated forums--Kaiser doctors and psychologists read every posting and often step in to give advice or correct misinformation. There's no advertising. One out of nine users reports finding data that saved him from seeing a doctor; an identical percentage learned something that prompted them to come in.

Most important, says Annalisa Silvestre, who is in charge of the site, the online community is changing how Kaiser and its members learn about each other and about health: "Learning occurred in silos--between doctor and patient in an exam room or in surveys we sent out. But nothing brought it in through one gate. This does. We have a gold mine of information. I won't be surprised if one day an epidemic like AIDS is discovered this way." The process doesn't pay for itself yet, though it has increased member satisfaction with Kaiser. The financial payoff will come, Silvestre believes, partly in reduced costs as more people log on rather than phone with questions, but mostly when the site expands to offer automated transactions such as prescription refills and appointment scheduling.

One more instance: Xerox, which a couple of months ago brought together the company's "knowledge champions" for a two-day Knowledge Forum, the third such gathering. This year its focus was on customer-learning programs. Company Webmaster Bill MacLain, for example, told of the "Webmaster's knowledge base" he's created from all the queries he's received; among its byproducts is a database of every employee who has helped him answer customer questions. U.S. customer operations has, since 1996, been developing a "customer-connections tool" that gathers data that used to be separate: verbatim responses to three customer-satisfaction surveys, write-ups of site visits to and from customers, and other meetings. Among other benefits, the process has produced documented improvements in customer satisfaction and loyalty. Says Dan Holtshouse, director of corporate business strategy: "Capturing the verbatims, the exact words, the 'voice of the customer,' carries a lot of weight. It makes the customer's experience real, personal, and more actionable. Hearing the voice helps remove distance between us."

Closeness is what customer learning is all about, because you can't be close to someone who is not close to you. That's how, in an e-commerce environment, a customer-learning process can move you up the clickstream; how, online or off, it builds a valuable shared asset comprising comfort, trust, and meshed social as well as technical systems. As surely as information trumps inventory, communication trumps mere information.