Some features of transmission mechanisms in Bulletin Board System

Herding in humans is a form of convergent social behavior and one of trends in cognitive sciences. One of issues on herding is transmission mechanisms of thoughts or behaviour between agents, which affects the cognitive abilities of group or organization. In this paper, we try to analyze transmission mechanisms in Bulletin Board System (BBS). BBS is one of the most popular mediums of communication and information on the World Wide Web (WWW) in China. We model a tree structure emergent from reply relationship for BBS. Our analysis aims to answer three key questions: (a) what are properties of each post? (b) what can we find about the size distribution of cascades? and (c) do graphs of information cascades have common shapes? Experimental results prove that: (a) a large number of people just browse or reply a small number of posts, (b) the number of posts vs. the number of replies and the number of posts vs. the range of view count both obey the power-law distribution.