The Internet is both a challenge and an opportunity for media accountability. Newsrooms and citizens are adapting existing practices and developing new ones on news websites, weblogs and social media. This report offers the first comparative study on how these practices are being developed and perceived in thirteen countries in Europe (Bulgaria, Finland, France, Germany, the Netherlands, Poland, Serbia, United Kingdom), the Arab world (Jordan, Lebanon, Syria, Tunisia) and North America (USA). Through the analysis of data on the media systems and in-depth interviews with journalists, experts and activists, the study maps the initiatives performed by media organizations and explores media criticism projects promoted from outside the newsrooms. The concept of journalistic fields proposed by Bourdieu provides the contextual analysis of the diversity of countries. It articulates the relationships between the media and the political and economic fields to explain how they shape media accountability developments on the Internet. The role of media self-regulation institutions and the active user culture enabled by the Internet are other actors considered in the description of the tensions surrounding media accountability in the journalistic fields. In this context, the study suggests that media accountability online is being enacted in practices that vary from country to country depending on the perceptions of journalists and newsrooms about it, the interplay of accountability aims with economic and political goals of the media, and their positions in the dynamic struggle for credibility within the journalistic field. Few media accountability practices are widespread in the countries analyzed, and the actual developments are very uneven in terms of motivations, technical tools and workflows. The analysis shows that those countries where there are more active online practices (USA, UK) are some of those with lower trust of the public in the media. In other contexts, such as the Arab countries, the efforts towards media ...