The Information and Communication Technologies (ICT) associated with Internet are producing social changes and Journalism has not been left unaffected. The growing role of Internet in today’s world shows its transforming capacity in the field of information and communication. One of the latest novelties is the leading role of the public in the news process. The latter no longer merely consumes news stories prepared by professionals; it wants to give its opinion and to assume an active role in information; this is “Citizen Journalism”, by means of which many digital media are fomenting citizens’ participation through spaces housed on their web sites. The characteristics, tools, impact and consequences of this will be explored in order to understand, from a critical point of view, the nature and scope of this revolution.