Kevin, there’s an editable wiki page on the IndieWeb site that does document a lot of the past as well as the future social media “silo deaths” as well as some of the related data loss: https://indieweb.org/silo-deaths. (Content warning: it is depressing to think of the personal data loss indicated on this page.)
Like many, I’m all for the concept of A Domain of One’s Own and find it very similar to the driving forces and principles behind the #IndieWeb movement. There are a number of educators who are adding some of this IndieWeb technology (Webmention, WebSub, Micropub, Microsub) to their practices. I’d like to think that the stronger open web these movements support will improve areas like open pedagogy and OER.
I’m happy to help those interested in trying out any of these technologies either for themselves or in conjunction with their teaching.