Today a large amount of relevant information is available on line, published by official and unofficial sources, e.g., the coverage of terror attacks, market insights or leaks of information. In particular, in the last few years we have seen the emergence of the Social Network Site (SNS) phenomenon: Internet information sources constituted by linked data and connected users producing an extraordinary amount of heterogeneous content. Given the unprecedented availability of linked data concerning the life of hundreds of million people, the general objective of this research project is to study methodologies and develop techniques and tools to monitor Social Network Sites and to identify relevant structural and communication patterns.