A major issue in the study of semantic Web services concerns the matching problem of Web services. Various techniques for this problem have been proposed. Typical ones include FSM modeling, DAML-S ontology matching, description logics reasoning, and WSDL dual operation composition. They often assume the availability of concept semantic relations, based on which the capability satisfiability is evaluated. However, we find that the use of semantic relations alone in the satisfiability evaluation may lead to inappropriate results. In this paper, we study the problem and classify the existing techniques of satisfiability evaluation into three approaches, namely, set inclusion checking, concept coverage comparison and concept subsumption reasoning. Two different semantic interpretations, namely, capacity interpretation and restriction interpretation, are identified. However, each of the three approaches assumes only one interpretation and its evaluation is inapplicable to the other interpre...