The authors explored adolescents' literacy practices and identities on newly popular story-sharing platforms. For budding readers, writers, and designers, these sites represent new media ecologies. With a mixed-method case study of 40 globally dispersed adolescents, the authors chronicled literacy roles, identity stances, and practices on the story-sharing apps Wattpad and Figment. These media-ted practices proved consequential for the participants' sense of investment in what they did. Findings show that adolescents divergently invested in a social orientation toward writing and an orientation focused on textual output. Different genres of practice came to the forefront, depending on users' identity stances. Participants in these platforms took on various stances, ranging from friend to fan to reader to novice and expert writer, which cohered with attendant activities. The authors conclude with implications for research, design, and coordination of learning environments for adolescents, given the observed heterogeneity in stances, roles, practices, and experiences.