The coronavirus pandemic exacerbated long-standing educational inequities associated with technology access, learner agency, and participation in online learning. How were preservice and inservice educators supported in their pursuit of interest-driven professional learning that critically examined the unfolding impact of these inequities? This article describes how the Marginal Syllabus project rapidly iterated three public, online, and equity-oriented social annotation activities for educators that included: Facilitating social reading sessions which combined synchronous social annotation with videoconferencing conversation; a collaborative partnership with the Speculative Education Colloquium to augment reading opportunities for shared dialogue; and supporting teacher education courses participating in social annotation activities under remote learning circumstances. The article details three recommendations for supporting educators' technical and sociopolitical professional learning via social annotation, and notes directions for future research that can examine how annotation-powered conversation may productively inform more equitable pedagogy and student learning practices.