A big challenge, both to IT Service Providers and to their customers, is in attempting to define exactly what an IT vendor is and how their customers should expect to interact with them. Many people see IT Service Providers (we will call them ITSPs for short here) as a single type of animal but, in reality, ITSPs come in all shapes and sizes and need to be understood in order to leverage a relationship with them well. Even if we lack precise or universally accepted terms, the concepts are universal.