An important point John, and as you say, made even more significant by recent developments.
I wonder to what extent, if any, schools have undertaken research to explore the effects of their use of social media platforms? How have they helped schools (presumably?) communicate and connect more effectively with their local and broader communities? What have the benefits and drawbacks been? What unanticipated consequences have arisen and how were they addressed? And then to your final point, if #IndieWeb or federated solutions were offered or adopted as an alternative, how might the implementation and/or outcomes be different?