Service Thinking or Service Design Thinking is an approach to imagine, prototype and build the interaction between humans and organizations.
In Service Design Thinking we would say that every interaction that someone has with an organization can be designed in order to bring value both to the customer and the organization.
Go further?
I would recommend this article to go further: Service Design 101
This question was first asked to me on Quora where I answered it in these words in 2009.