The article studies how civil society performs its functions while civic activism is transiting to digital forms and how different participatory models of interaction between society and government are developed. According to the authors, digital technologies create fundamentally new opportunities in ensuring a dialogue between authorities and society, and also support young people to overcome their political and civil absenteeism. The article provides the author’s classification of functions that civil society actualize in online activism: in particular, such functions as solidarizing, socializing, mediating, monitoring, articulating and mobilizing are highlighted. The way how civil society performs its functions in online activism is examined based on results of the sociological survey with 1,150 young respondents from the Sverdlovsk region, all being 14-25 years old and representing the digital natives’ generation. An analysis of each function was carried out: how these young people assess possibilities of digital participation, if these functions are part of their motivation for participating in civic activism, how these functions are implemented in real practices of digital activism. Then conclusions are drawn concerning the level of relevance for each of the highlighted functions of civil society and possibilities of their implementation via digital technologies. Finally, young people appeared to highly appreciate effectiveness of online projects, they are involved in various forms of digital participation and public agenda formation. Our research determined certain prospects for studying digital activism in the context of digital practices of interaction between youth and authorities, the role of social media in communication between authorities and the public, etc. Our work proved to be significant for identifying updates in functions performed by civil society, expanding scientific ideas concerning digital participatory culture of youth and its role in civil society development. It is also promising in identifying new areas of youth policy regarding co-participation and digital citizenship. Our research results can be applied for supporting and promoting projects and educational programs in the field of digital activism associated with young people.