What is a service?

Services are software chunks, or components, constructed so that they can easily linked with other software components. Services/software components carry out business processes.

• Services have well defined interfaces.
• Services are the interfaces to the business logic.
• A service is the endpoint of connection.
• Services are connected to each other with loosely coupled connections.
• Services are coarse grained, meaning the service can perform its logic and return the result in a single call.
• Services do not contain presentation logic, so they may be reused across diverse applications.

The important thing over here is technology should be expressed in chunks that business people can understand rather than as an application like ERP, CRM, etc. I will come back with more technical details regarding services later. I just need to elaborate more on loose coupling.