FEEDBACK. High-tech bells and whistles aside, how does this differ from previous efforts to ''delight'' customers? Wingspan invites customers to refine the bank's offerings. ''Our customers have a great desire to improve the bank, and we act on their ideas,'' says Clearly. Customer feedback led to software changes that allowed users to access all their accounts at once, with a single sign-on. In response to customer suggestions, the bank is working on a way to allow deposits at ATMs and to improve downloads of financial data from Wingspan servers to customers' Quicken software.

The best-of-breed companies will go even further. They'll invite customers in as collaborators, binding them ever tighter to the corporation. Procter & Gamble Co. (PG) spin-off reflect.com LLC, an online cosmetics merchant, is a harbinger of what's possible. By answering a series of queries ranging from color preferences to skin type, consumers can custom-design up to 50,000 different formulations of cosmetics and perfumes. When they're done, they can even design the packaging.

for the products. Procter & Gamble charges a premium price for the custom-blended blushers and lipsticks, and why not? Customers mixing their own shades aren't likely to try comparison shopping.

Reflect.com is one of many efforts to create enduring relationships with customers in an age of commoditization. ''The next level up is where the consumer is really designing from scratch,'' says Ticoll of Digital 4Sight. ''Organizations will learn from these new opportunities.''

Applied correctly, this kind of mass customization can yield remarkable efficiencies. Already, Dell Computer Inc. (DELL) generates more working capital than it consumes because its customers specify and pay for product before Dell has to pay suppliers. In contrast, Honeywell International Inc. has $3.5 billion of working capital tied up at any given time. The key to Dell's remarkable feat lies in the company's made-to-order business model, which greatly limits inventory. Already, the company turns over its tiny inventory 60 times a year, a tenfold improvement from 1994. The result is obvious: Dell's.

customers finance the company's growth so it does not have to take on debt. Mass customization also allows Dell to make only the products it will sell. So there are no write-downs or discounts to move unwanted or outdated merchandise.