Can a marketer be trusted with sensitive personal and financial information? Consumers increasingly expect their identity and personal information to remain confidential when they go on-line to shop, and that, coupled with fear of on-line fraud, is what stops many consumers from even considering digital transactions.

The Georgia Institute of Technology, in its "Tenth WWW User Survey," found that only 4 percent of on-line users routinely register at Web sites, and at some sites two-thirds of those not registering report a lack of trust as one of their reasons. They will become buyers only when marketers overcome the lack of trust that paralyzes many would-be Net shoppers. In response to those security concerns, marketers are working to build trust with consumers through their on-line interactions. The level of trust grows as marketers and consumers engage in a gradual "value exchange," through which consumers provide marketers with personal information and are rewarded in turn with products they actually want.

McKinsey research on more than 50 e-businesses shows that the on-line marketers pacing their industries do so by embedding trust into their interactions with consumers. They are forging a broad logic of trust based on constant and interactive value exchange between...