With remarkable frequency, people who tout Web services as The Next Big Thing always begin by trashing wireless. Wireless requires massive investment in infrastructure; Web services use current infrastructure. Wireless offers expensive solutions to problems that never existed; Web services offer cost-effective solutions to everyday IT problems.

The message is that the Web services concept stands apart in its common sense. It’s a simple idea: Enterprise applications should be broken down into reusable components called services, each one performing a distinct task. These services can then link together across or within enterprises using the only data exchange standard everyone can agree on, XML. Like a kid stacking toy blocks, you can build applications from Web services very quickly, borrowing blocks from others when you need them.

Drawing on systems as disparate as a Hitachi mainframe and an NT server, for example, insurance company execs could click and drag Web services to create one-off packages. Car rental and airline reservation systems could integrate across the Internet with minimal development effort. Once you break applications into Web services, low IT overhead makes such experimentation practical?or so the theory goes.

"We’ve been talking about modular and object-oriented software for years, and in many ways this is nothing more than the realization of that," says Frank Moss, chairman and cofounder of Bowstreet, an enterprise portal provider that is building its business on Web services. "It’s finally happening due to the emergence of XML as the standard for interoperability. All computing is going to become Web services."

A statement like that would stretch credibility but for the all-star cast supporting it, including HP, IBM, Microsoft, Oracle and Sun. Predictably, each vendor has a self-interested spin on Web services. And the Web services world has already split in two, with Microsoft’s .Net promoting services that run only on Windows while the J2EE (Java 2 Enterprise Edition) crowd pushes its own platform-agnostic, Java-specific solution.

Yet the chorus of heartfelt endorsements can’t be ignored. IBM has even deployed its own Web services evangelist, Steve Holbrook, who cheerfully asserts to anyone who will listen that Web services "is going to happen more rapidly than we’ve seen integration efforts happen before."

Weaving the Services Web

Holbrook’s optimism stems in part from the accord on key Web services standards by industry heavyweights who normally agree on very little. Such harmony is essential, because XML by itself merely describes a broad framework. Three, more narrow standards?Simple Object Access Protocol (SOAP); Web Services Description Language (WSDL); and Universal Description, Discovery and Integration (UDDI)?enable Web services to talk to one another. (See "Web Services Standards," this page.)