My friend @sandro (who also was the W3C staff member on the Social Working Group as it turns out) has put together a chart about "ways to harm people online" (whether you agree all are harms, most are, and all are claimed as such) that I think is really useful: https://docs.google.com/document/d/1ZQDWwh3J6c_RAVlIAPAKI6eRB4HI7HlrBwAJrP8btkQ/edit
What's interesting is that most of these are about harm caused by *distributing* information.
(arguably, this is true even in a centralized system, and preventing these things through centralized control is usually constructed where only the powerful get to prevent anything)
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