Because social technologies present illuminating educational, ethical, economic, and structural challenges to existing constructions of public education, they catalyze a fundamental examination of what public education should look like and be like in a democracy. Given their performances in other arenas, mobile and electronic technologies have the potential to further critical pedagogical praxis by enabling more democratic and participatory discursive practices. At the same time, they are significant vectors for market infiltration. They intensify surveillance, reproduce existing structures, and constrain conceptions of the possible. To examine what emerges regarding the construction of teacher as a subject when these latest technologies are incorporated, this article reports on findings from a multiple case study of five secondary school teachers using social media in their teaching.