Social media platforms have transformed how students and educators "share" information about school experiences. In this paper, we translate Leah Plunkett's sharenting concept (a portmanteau of "share" and "parent") to address the phenomenon of "overposting" in education. Overposting (a portmanteau of "overreach" and "post") designates the digital distribution of information about others that is invasive, harmful, exploitative, or illegal. We describe instances where students or teachers post about others on social media in ways that are illegal, invasive, harmful, or exploitative. Examples of overposting range from cyberbullying to sharing photos or videos of others' without their permission, including from school accounts. We conclude by offering an educational approach to address overposting through education, conversation, and negotiation among students, teachers, and administrators.