This idea was first described to me by Albert Strasheim.
Vanaf http://en.wikipedia.org/wiki/Service-oriented_architecture :
In computing, the term Service-Oriented Architecture (SOA [pronounced "es-ō-ā"]) expresses a perspective of software architecture that defines the use of services to support the requirements of software users. In an SOA environment, resources on a network are made available as independent services that can be accessed without knowledge of their underlying platform implementation.