Following on the heels of the service-oriented architecture, the service-oriented business application is generating the latest buzz in distributed computing. While distinguishing between SOA and SOBA isn't easy - since both terms are used to describe constructing application infrastructures from Web services - the idea is that SOBA can be deployed on top of SOA, or other infrastructure models. The term's creator positions SOBA as the ultimate incarnation of the client/server business application - ERP, CRM and others - that has become today's monolithic beast.

"A SOBA is a client/server application done right," says Charles Abrams, a Gartner research director, who coined the term more than two years ago. "It is a business application that is centered on Web services standards."

In Gartner's model, SOBA ranges from today's simple XML interfaces overlaid on a current application to a far more sophisticated application infrastructure that will evolve. Rudimentary SOBAs are legacy applications modified with a Web services interface based on Simple Object Access Protocol . SOBA variants on the horizon include: best-of-breed components for broad deployment in horizontal or vertical markets; modular corporate suites from vendors such as Oracle and SAP; and SOBAs constructed from multiple services developed internally within corporations, sold by vendors or built by system integrators and service providers.

As the sophistication ratchets up, users will need tools such as metadata repositories to smooth data format issues along with Web services standards for functions such as reliable messaging, transactions, management and business process orchestration. Those standards are in various forms of development today and represent a major speed bump on the SOBA road. Eventually, SOBA will be wholly constructed using network-based application services - as discrete as validating a purchase order - that are combined on the fly with other services to execute a business process, such as a transaction with a business partner.