This chapter presents the different jurisdictional claims between whistleblowing platforms and investigative journalism with regard to the establishment of their professional boundaries. Whistleblowing platforms can be considered as a clear example signalling the expansion of the boundaries of journalism and of its hybridisation with other cultures and ethics, those of hacking in this case. The phenomenon of boundary crossing, as well as the growing forms of hybrid journalism resulting from different professions working together, can be systematically analysed with the help of the concept of boundary work, developed by Thomas Gieryn in the field of the sociology of science. The Internet not only facilitates the implementation of accountability practices and instruments, but it also eases the media user’s participation. The tripartition of the accountability concept along the production phases is useful to establish an overall evaluation of the transparency and responsiveness of whistleblowing platforms, particularly in the light of the growing calls for more transparency and accountability.