The ever-growing number of services on the WWW provides enormous business opportunities. Services can be automatically discovered and invoked, or even be dynamically composed from more simples ones. In this paper we concentrate on the problem of service discovery. Most current approaches base their search on inputs and outputs of the service. Some of them also take into account preconditions and effects, and other parameters that describe the service. We present a new approach that complement existing ones by considering the types of interactions that services can be used in. We present our proposal for a concrete application based on a real-world scenario for emergency assistance in the healthcare domain.