In recent years, the political arena has been transformed into a space of public debate, a phenomenon which is both evident, yet hitherto unparalleled. A new range of digital social communication tools framed within the Web 2.0 era, with the blog often proving the tool of choice, has displaced the traditional pre-eminence of the communication scenario, as previously used by the mass media, thanks to a series of more interactive, diverse and credible dynamics which place the user at the very heart of the political discussion process and facilitates processes of social mobilization and collective civic action. This study takes the above situation as its point of departure and guiding principle to propose and define political blogs as a new means of creating information and opinion, and communicating and occasioning effective influence in public agenda-setting. This theoretical work undertakes a detailed critical analysis of the potential of these tools and explains the extent to which they should be considered appropriate platforms for the communication and discussion of public issues. Moreover, it will also consider their engagement in a new, more open form of citizen journalism, free of the bias and pressures exerted by large media corporations, thus creating a digital public sphere with far greater capacity and agency for change.