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 take for this vision to materialize? The substantial investments in Web services that players such as IBM, Microsoft, and Sun Microsystems are now making have convinced some observers that this technology will soon be a reality. Others point to the significant remaining hurdles: key technical standards still haven’t been finished; specific services and new service providers have yet to be defined; and, perhaps most important, questions such as consumer privacy and security remain unanswered.

Despite these obstacles, new and potentially powerful innovations are building behind the buzz. Click through the following exhibits for a look at the new world of Web services.