Wikipedia
Service-orientation
Service-orientation is a design paradigm for computer software in the form of services. The principles of service-orientation design stress the separation of concerns in the software. Applying service-orientation results in units of software partitioned into operational capabilities, each designed to solve an individual concern. These units qualify as services.
Service-orientation has received a lot of attention since 2005 due to the benefits it promises. These include increased return on investment, organisational agility and interoperability as well as a better alignment between business and IT. It builds heavily on earlier design paradigms and enhances them with standardisation, loose coupling and business involvement.