Anyone made leery by the unfulfilled promises of the dot-com era may feel skeptical, or at least confused, about Web services, the latest wave of innovation on the Internet. Sky-high expectations and reams of hype are too often the death knell for emerging technologies. Will this one be any different?

At the risk of soliciting conversions to a potentially false creed, we offer a primer on Web services—what they are, what you need to know to be conversant with the underlying technology, and why, in the end, you may decide to pay closer attention as they evolve.

Simply put, Web services are business and consumer applications, delivered over the Internet, that users can select and combine through almost any device from personal computers to mobile phones. By using a set of common protocols and standards, these applications will permit disparate systems to "talk" with one another—that is, to share data and services—without requiring human beings to translate the conversation. The result promises to be "on-the-fly" (real-time) links among the on-line processes of different companies. These links could shrink corporate IT departments, foster new interactions among businesses, and create a more user-friendly World Wide Web for consumers.

What will it...