, or the so called Web 2.0, is growing daily by the number of users and applications. In this way, a significant part of newly generated Web content and traffic is created by the users itself. They create, connect, comment, tag, rate, remix, upload, download, new or existing resources in an architecture of participation, where user contribution and interaction adds value. Users are also involved in a broad range of social activities like creating social relationships, recommending and sharing resources with friends, creating groups and communities, commenting friends activities and profiles and so on. But not only users benefit from the user-generated content, also social applications profit from that content by using it for personalization and adaptation to user needs.