The article is devoted to a systematic study of the online pseudonyms used by authors of a new genre of popular culture ‒ fan literature (fanfiction). A review of the scientific literature on the topic reveals that the system of virtual pseudonymy is increasingly attracting the attention of linguists. However, its theoretical understanding remains a controversial issue in both Ukrainian and foreign linguistic circles. Based on a pragmatic-communicative analysis, the article establishes an irrefutable connection between network pseudonyms and the personal identity of their bearers. It has been found that the network autonyms of fan literature creators are primarily intended to ensure a person’s membership in a virtual community by enabling registration on a web resource. They also express various components of the author’s individual identity: they mark a person as an amateur artist, express their attitude toward the virtual community and their vision of their place in it, and emphasize certain personal characteristics. In terms of the principles of creation, the studied proper names largely coincide with traditional artistic pseudonyms while also revealing specific features related to the increased attention to the visual form of the name, its length, and the choice of nominal models. This is due to the established traditions and existing technical limitations in the virtual environment. The theoretical substantiation of the phenomenon of online pseudonymity is supplemented by a description of the linguistic features of the online pseudonyms used by fanfic authors. Since the practical study of Internet pseudonyms is characterized by a multiplicity of analytical approaches, an attempt is made to systematically describe the analyzed group of self-names based on the following criteria: motivation, method of creation, features of structure, and semantics. It is shown that the nominative trends in the analyzed community, although largely based on traditional anthroponymic formulas, tend to maximize the formal, grammatical, and semantic differentiation of the constituent bases. This indicates that the authors are revealing their creative potential, and their pseudonyms testify to the heterogeneity of the cultural community. The network pseudonyms of users in the Ukrainian-language segment of the Internet form a diverse and dynamic system, which highlights its prospects for further research.