Online monitoring, filtering, blocking ….What is the difference? Where to draw the line?

Filtering technologies were initially conceived as users' friendly tools. But this did not last very long and the opacity of these technologies has progressively become more “visible”. The lists of blocked sites are most of the time kept secret. What is less often underlined though is that filtering technologies in several cases operate as mechanisms of mass surveillance of online behaviour. Given the inherent defects of these technologies, the question is then why the imposition of a duty to systematically monitor information online has not really been seen as problematic by judges, be they national or supra-national. It is indeed argued in this paper that the recent CJEU's judgments do not seem in the end to be very demanding. Two reasons at least can explain the “pragmatic” approaches of judges. First, the focus seems to ultimately be set upon the outcome legitimacy of the use of filtering technologies. This, however, hides in some cases a significant alteration of the prescription of the law and/or a transformation of its fundamental function. Second, the distinction between limited and general monitoring obligations has never been clearly drawn. As a result, the distinction between mass surveillance and targeted surveillance appears to become irrelevant in the online world. The purpose of this paper is thus to streamline the terminology used in the field in order to highlight the flaws of the legal framework.