Contemporary Internet is highly interactive. This research concerns the impact of development of the Internet on the liability of intermediary service providers (ISP) for illegal user-generated content (e.g. copyright infringement or defamation) adopting a multidisciplinary approach (legal, social, technical, etc.). The main question is how to shape the ISP liability in «the Web 2.0 era»? This introductory essay forms a part of the author’s research for the master thesis in law and technology at the Tilburg Institute for Law, Technology, and Society (TILT).