This is not a solution to the real problem: social networks having in-depth knowledge about the whole population. By all means, I don't want to discourage anyo

This is not a solution to the real problem: social networks having in-depth knowledge about the whole population. By all means, I don't want to discourage anyone from self-hosting. The problem is: There will always be agents (private people or companies) who leak information about others (on purpose or because of a lack of concern) which allows shadow profiling of people who want to opt out. Furthermore, these agents don't necessarily grasp the dangers which the disclosure of their social network brings for them. What we need are stronger laws as to what social networks (and other services) are allowed to store. For instance, FB shouldn't be allowed to know anything about me without me consenting to it.