Online service providers (OSPs)-such as AOL, Facebook, Google, Microsoft, and Twitter-significantly shape the informational environment (infosphere) and influence users' experiences and interactions within it. There is a general agreement on the centrality of OSPs in information societies, but little consensus about what principles should shape their moral responsibilities and practices. In this article, we analyse the main contributions to the debate on the moral responsibilities of OSPs. By endorsing the method of the levels of abstract (LoAs), we first analyse the moral responsibilities of OSPs in the web (LoAIN). These concern the management of online information, which includes information filtering, Internet censorship, the circulation of harmful content, and the implementation and fostering of human rights (including privacy). We then consider the moral responsibilities ascribed to OSPs on the web (LoAON) and focus on the existing legal regulation of access to users' data. The overall analysis provides an overview of the current state of the debate and highlights two main results. First, topics related to OSPs' public role-especially their gatekeeping function, their corporate social responsibilities, and their role in implementing and fostering human rights-have acquired increasing relevance in the specialised literature. Second, there is a lack of an ethical framework that can (a) define OSPs' responsibilities, and (b) provide the fundamental sharable principles necessary to guide OSPs' conduct within the multicultural and international context in which they operate. This article contributes to the ethical framework necessary to deal with (a) and (b) by endorsing a LoA enabling the definition of the responsibilities of OSPs with respect to the well-being of the infosphere and of the entities inhabiting it (LoA(For)).
