In literary studies, the phenomenon of fan fiction remains controversial, with its key feature being identified as its secondary nature. The purpose of this work is to substantiate that in the context of postmodern literature’s transmediality, the secondary nature of fan fiction is relative, but there is a common genre-poetic distinctiveness of texts that is transmitted into original literature, and in the case of fan writers’ monetization of their creativity – into professional literature. An analysis of media data from the Russian platform https://ficbook.net/ shows that the degree of connection between fanfics and the canon and the nature of secondary processing varies widely: from direct stylistic imitation to variations and remakes to original texts. The diversity of fanfics is united by the dominance of the psychological romanticism poetics, reflected in the artistic distinctiveness of the texts and in the genre preferences of fan writers. The hero is a person caught up in emotions and internal upheavals. Motifs of fate reversal, confrontation with the extraordinary, discovery of a secret help to launch or exacerbate a conflict with oneself, reality, or the object of passion. Special attention is paid to lyrical experiences. The romantic vector determines the genre priorities. Genres: alternative universe, drama, angst follow immediately after romance, which takes first place on Ficbook. The focus on a person’s inner world is additionally emphasized using frequent subgenre characteristics: love/hate, denial of feelings, relationship development, hero’s growth. The article argues that fan fiction goes beyond the boundaries of secondary literature and becomes a part of the contemporary popular literature, bringing its own distinctive genre-poetic imprint.