It seems reasonable to summarise evolved principles of service orientation in one place. Following list comprises pairs of principle name - definition. Each principle links to the related post discussing the principle evolution.
Note: when 'service provider' entity appears in the definition of the principle, we mean that related activity may be performed either by the service provider, or by the service own, or by the service steward.
Standardized Definition of Service Contracts
Service contracts are in compliance with the standardised definitions of the contract content types and represent mutual agreements between service provider and service consumers
Service Loose Coupling
Service contracts impose low consumer coupling requirements and are themselves loosely decoupled with their surrounding environment via execution contexts
Service contract only contains essential service information that is agreed between the service provider or service owner and the service consumer(s). The information has to be sufficient for interacting with the service, utilizing agreed service functionality and reaching agreed Real World Effect
Services contain and express logic that can be reused in the execution contexts; services can be positioned as reusable enterprise resources
Service Relative Autonomy
Services exercise a relative level of control over their underlying runtime execution environment; if the service does not own or control used entities such as resources or other utilised services, the service must posses contractual control over the use of those entities
Service State Management
Services minimize resource consumption by deferring the management of state information when necessary
Services are effective composition participants as well as effective composition containers, regardless of the size and complexity of the composition
Services are supplemented with communicative meta data by which they can be effectively discovered and interpreted
[NEW] Service Execution Context
Services perform in surrounding business and technical runtime environment that constitutes service execution context. The service execution context can affect reachability, behaviour and results (Real World Effect) of the services
[NEW] Service Separation of Concerns
Business services have to own and provide only their own functionality being independent from the information sources and original information structures as much as possible
The reviewed principles of Service Orientation reflect contemporary understanding of the Service Orientation as a methodology of constructing Business and Technology parts of the organisations and as the directive for designing corporate products. The latter are provided by the organisation for its internal and external consumers in the form of the business services.