Abstract — Understanding information diffusion processes that take place on the Web, specially in social media, is a fundamental step towards the design of effective information diffusion mechanisms, recommendation systems, and viral marketing. Two key concepts in information diffusion are influence and relevance. Ability to popularize content in an online community is the influence. Influentials introduce relevant content, in the sense that such content satisfies the information needs of a significant portion of this community.We describe the problem of identifying influential users and relevant content in information diffusion data and also study how individual behavior data may provide knowledge regarding influence relationships in a social network in this paper.