This paper presents a case study of the multilingual writing practices of a Serbian university student on Facebook, examining how he uses multiple varieties of English and Serbian images and video to shape his online identity and establish membership in local and global communities. Drawing on data from stimulated-recall interviews, online participant observation, and rhetorical analysis, this study shows how Aleksandar, a hip-hop artist, appropriates hip-hop codes and employs the "gate-keeping" function of posting links (Baek, Holton, Harp, & Yaschur, 2011) by embedding links to music videos in his own highly personal code-mixed text in order to establish himself as a distinctly Serbian member of the global hip-hop community. The findings suggest that Aleksandar's language practices and attitudes might be better understood as translingual (Canagarajah, 2011), as the student integrates diverse linguistic and semiotic resources into a unified expression of identity, relying on the multimodal affordances of digital writing to accomplish his communicative goals. However, these sophisticated textual practices go undervalued in his EFL writing courses, where formal, monolingual, non-digital literacy remains primary (Saxena, 2011). These findings suggest a need to re-evaluate what it means to have a second language-mediated identity, and to expand the focus of EFL writing pedagogy.