Trust 2.0: Who to believe in the flood of online data?

The Internet and the World Wide Web together form a globally distributed network that provides a ubiquitous medium for interaction, the exchange of ideas, and commerce. The web is pervading our everyday lives in ways that were unimaginable even ten years ago. The evolving use of the web requires robust and efficient trust and reputation management mechanisms. Despite numerous proposals on trust and reputation systems, designing a robust and reliable system is still largely an open challenge, especially in the vast social networks that have become popular. A goal of this paper is to describe the critical open challenges that limit the effectiveness of today´s trust and reputation systems. We first provide a comprehensive literature review. Moreover, we present a set of our contributions as a way to address some of these challenges. We also propose a future research agenda for trust and reputation systems.