New technologies pose new challenges on the protection of privacy and they stimulate new debates on the scope of privacy. Such debates usually concern the individuals’ right to control the flow of his or her personal information. The article however discusses new challenges posed by new technologies in terms of their impact on groups and their privacy. Two main challenges are being identified in this regard, both having to do with the formation of groups through the involvement of algorithms and the lack of civil awareness regarding the consequences of this involvement. On the one hand, there is the phenomenon of groups being created on the basis of big data without the members of such groups being aware of having been assigned and being treated as part of a certain group. Here, the challenge concerns the limits of personal law, manifesting with the disability of individuals to address possible violations of their right to privacy since they are not aware of them. On the other hand, commercially driven Websites influence the way in which groups form, grow and communicate when doing this online and they do this in such subtle way, that members oftentimes do not take into account this influence. This is why one could speak of a kind of domination here, which calls for legal regulation. The article presents different approaches addressing and dealing with those two challenges, discussing their strengths and weaknesses. Finally, a conclusion gathers the insights reached by the different approaches discussed and reflects on future challenges for further research on group privacy in times of big data.