Searching social networks is determined by two factors: reputation and relevance. Reputation is the memory and summary of behavior from past transactions. Relevance is the probability that useful information can be obtained from a person. Search in social networks is performed by asking persons of high relevance and a good reputation or persons who are supposed to know somebody like that. We describe how these social aspects can be used in peer-to-peer networks in order to increase efficiency and scalability. Based on a social peer-to-peer network a knowledge management application with advantages over centralized approaches can be implemented.