Imagine a one-stop shop where you can arrange any service--airline reservations, shipping packages, appliance repair--through any supplier. Amazon.com lets us buy almost any product from any manufacturer, but where can we go to order services through one consistent interface?

In this presentation at Burton Group's 2005 Catalyst Conference, Mark Orttung of Rearden Commerce describes his project, started in 2000, to do just that. A project that, he says, would be impossible without the advent of Service-Oriented Architecture (SOA) and Web Services.

He calls it "Services on Demand" and says InfoWorld calls it the killer app of SOA.

Rearden created both an architecture and an application. Mark argues that neither would be successful without the other: The application uncovers real-world requirements, and the framework enables rapidly adding new services and service providers.

He says the application drives cost savings and productivity for corporations. It allows employees to purchase services within the corporate controls--using preferred suppliers, for example. The application must integrate with the "fabric of daily life," keeping the user's calendar updated, inviting colleagues, and coordinating small groups. It must integrate with the corporation's HR system, groupware system, and so on, all through SOA.

The Q&A covers how many services and suppliers are available and what fraction of them through web services vs. wrapping HTML interfaces. Also questions on calendar interoperability and handling complex XML schemas. In response to a question about the similarity of Rearden's architecture to Universal Description, Discovery, and Integration (UDDI), Mark expresses skepticism about UDDI in general. But he agrees that his application is sort of a trusted version of a UDDI directory, enabling employees to interact with preferred suppliers.