Abstract
In this study, user interaction in virtual communities are investigated using social network analysis in order to realize which conditions of community would result in large amount of people affected to have high purchase intention. We would also like to examine whether influences of opinion leaders are greater than the condition of network structure formed by on-line users. Besides, Brand awareness and price are also taken into account to see if they would moderate the relations between social network index and purchase intention. The conclusion is that influences of opinion leaders are not greater than number of cliques and degree of clique overlap in virtual communities. Nevertheless, opinion leader is important regarding to a brand which has lower brand awareness.