Online Social networks have become popular with the increased use of mobile devices. Online Social network analysis alleviates the quantitative as well as qualitative analysis of online social networks. Online social networks deals with human emotions and communications, the vagueness in the process is more and is a hindrance in computation. We analyze two network measures namely centrality and prestige by developing a fuzzy rule based inference system. We obtained the relation between interaction, centrality and prestige in online social networks. The paper describes in detail, the need for a fuzzy approach in online social network analysis and analyzes the network measures. © 2016 ACM.