When Computers Learn to Talk: A Web Services Primer; What Are Web Services? Why Should You Care?

Any one made leery by the unfulfilled promises of the dot-corn 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. Is this one going to 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 must know to be conversant with the underlying technology, and why, in the end, you may decide to pay closer attention as they evolve. To put it simply, 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 shared 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? Although certain aspects of the technology (security, for example) are still maturing, the substantial Web services investments that companies 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 are still incomplete; specific services and new service providers have yet to be defined; and, perhaps most important, major questions about consumer privacy and security remain unanswered. Despite these obstacles, new and potentially powerful innovations are building behind the buzz. What are Web services? The hype around Web services reflects their potential for helping computers talk with one another more easily (Exhibit 1). These conversations will take place through new Internet standards and protocols that allow computer applications to reach beyond the confines of operating systems, programming languages, and middleware (see sidebar, "What does the terminology mean?"). The lingua franca of this machine-tomachine discourse will be the Extensible Markup Language (XML), which "tags" digital content in standardized formats. Once computers have been linked in this way, it will be possible for consumers to access a more seamless World Wide Web from many different devices, while businesses will be able to connect their operations quickly and cheaply and thereby cut their transaction costs and improve their customer service. Putting client-server Computing on the Web Web services implement the client-server model over the World Wide Web (Exhibit 2, on the previous page). On the client side, for example, they manage the different screen shapes and sizes and the different connection speeds of desktop computers, mobile telephones, and PDAs. On the server side, the various programming languages and middleware technologies at work behind each application or data source become transparent to programmers, so it is a lot easier for them to develop applications. Creating a user profile Passwords and other kinds of information about users will be stored in the form of Universal User Profiles (UUPs), giving them easy access to any number of Web sites and services, through a variety of devices and in a variety of roles-for example, that of customer or employee (Exhibit 3). Each UUP will probably be stored with a service provider, such as AOL Magic Carpet (also known, less engagingly, as Screen Name Service) and Microsoft.NET Passport. Once users registered with a provider, they would own this "sticky" information, at least nominally, and other Web sites and services would be permitted to interact with them. …