This study explores a second-grade English language learner's literacy development and ability to use blogging for social and academic purposes, in the context of learning academic writing genres in a US urban school. Grounded in sociocultural theories, it conceptualizes learning as appropriation, and language as a dynamic and functional system of semiotic resources. Data included written texts, blog postings, videotaped classroom interactions, informal conversations, interviews, instructional materials, and school documents. Data analysis, using qualitative coding procedures and systemic functional linguistics, focused on appropriation of blogging and language use. The findings show that the child appropriated blogging to gain recognition for his social and academic status among peers and to solve problems. These appropriations enabled the student not only to construct new social relations in and out of the class, but also to have a critical view of linguistic choices, demonstrating emergent knowledge of the interpersonal function of texts and the interrelation between interpersonal and experiential functions. The implications of the study relate to use of Web 2.0 tools for emergent literacy development and conceptualization of digital literacies.