Here’s Sangiorgi on a key distinction:
I like to consider the origin of Service Design field with the introduction of the Interaction paradigm. Meaning moving the conception of services as complex organisations to the one of services as complex interfaces. In my opinion the perspective that looks at services from the interaction point of view, is different from the one that was trying to define services as ‘products’ and therefore as objects of a design process.
It sounds like she’s framing service design as a third order rather than a second order problem. By “interaction” she’s referring to services as complex interfaces between providers and users. A system of subjects, artifacts, roles and norms.
Here’s a recap of her talk by STBY.
I stumbled across an earlier paper (pdf) of hers on the topic of service design and activity theory a while back. Translating it from Italian proved incomprehensible so I put it aside.
This newer presentation clears up a lot.”