Leveraging Users' Trust and Reputation in Social Networks

In on line communities, where there is a vaste number of users that interact under anomymous identities, it has been observed that e-word of mouth is a very powerful influence tool. So far, this technology is well known in on-line marketplaces, such as Amazon1, eBay2 or travel based platforms like Tripadvisor or Booking. However, these trust based approach can be leverage in other scenarios from e-democracy to trust based recommendations on e-health context and e-learning systems. The purpose of this contribution is to analyse the main existing trust and reputation mechanisms and to point out new research challenges that needs to be acomplished with the objective of fully exploiting these systems in real world on-line communities.