An effective and efficient approach in designing software systems to describe system requirements is using scenarios. A scenario, commonly shown as a message sequence chart or a sequence diagram, is a temporal sequence of messages sent between system components. Scenarios are appealing because of their expressive power and simplicity. Moreover due to the clear and concise syntactic of scenarios, they can be used to analyze the system requirements for general validity, lack of deadlock, and existence of emergent behavior. Emergent behavior or implied scenarios are specifications of behavior that are derived from compiling of all requirements together but are not explicitly specified in the set of scenarios. Although emergent behavior is not necessarily unwanted, nevertheless it is useful for system designers and engineers to be aware of its existence. Defining requirements using scenarios and conducting consequent analysis has been done for distributed systems as well as multi-agent system. In this research the requirements of a social network are described using scenarios. The scenarios are then used to detect emergent behavior using a systematic methodology. This is illustrated using a prototype of a social network of MAS for semantic search that blends the search and ontological concept learning.