Following this approach consistently produces a set of interfaces that define the relationship between our application and the rest of the world in our application’s terms and discourages low-level technical concepts from leaking into the application domain model.

benefits:

• define the relationship of

• • our application

  • the rest of the world

• in our application’s terms

• prevent low-level technical concepts in domain model

(src: Book: Growing Object Oriented Software, Guided By Tests - Steve Freeman & Nat Pryce)