A growing number of companies are finding that lower-visibility Web-oriented architecture (WOA) developments, spawned through grassroots movements, are a better route to the service-oriented architecture. WOA, like SOA, is an architectural approach to system design, though WOA is resource-oriented rather than service-oriented. What's the difference? While the core SOA design unit is a reusable service that fulfills a distinct business function, resource-oriented services are more limited and data-focused.
SOA and WOA work at different layers of abstraction. SOA is a system-level architectural style that tries to implement new business capabilities so that they can be consumed by many applications. WOA is an interface-level architectural style that focuses on the means by which these service capabilities are exposed to consumers. Governance, quality of service, security, and management are of equal importance, whether the functionality is being delivered via SOA or WOA.
Source: Information Week, http://www.informationweek.com