Bridging the Gap between the User's Digital and Physical Worlds with Compelling Real Life Social Applications

Nowadays, the majority of web sites and web-based applications encourage their users to engage in social interactions such as adding comments, expressing opinions or sharing content with their friends in social networking websites. Social activities involve basically: (i) users, (ii) user generated content -UGCthat users create and share and (iii) resources that are described with the created content. The logical structure of the underlying knowledge emerges as a set of links between the three aforementioned components. More concretely, a user generally annotates resources with different forms of user generated content, like social annotations, tags or links. As a consequence, huge amounts of shared social data are now available, which raises new challenges for information management and discovery. Each social interaction represents an opportunity to create valuable knowledge that can be further leveraged for added-value services (e.g. recommendation or prediction)