There has been alot of discussion recently about how to fix social networks. It seems to be a point of near consensus that engagement-driven metrics are a problem, and that they are the result of the commercial nature of these services. One of the central points of debate seems to be about how an organization could run a free social network in an ethically and financially sustainable way. In contrast I haven't seen much discussion of a government run option.
Planning, providing and maintaining public spaces is already one of the key functions of government. It also seems that the cost of running a social network may not actually be that large if there isn't any tracking/targeting infrastructure to maintain. There is no fundamental reason users should have to upload their photos/video to the social network itself either, we've just become accustomed to it.
In the US, the first amendment would apply in full force, as this would not be a privately run service. Constitutionally protected speech would remain protected. A company administering a social network must inevitably make judgment calls about moderation, which inevitably creates controversy. Removing this possibility and having moderation constrained by law provides some measure of transparency and accountability, and provides a clear path forward for citizens to determine how the service is operated.
Privacy would have to be guaranteed. Protections given to physical postal mail might be a reasonable starting point. A postal worker isn't allowed to read your mail even when asked nicely by an FBI agent without a warrant. There would be legislative attacks on this kind of privacy, but then people's attention would be focused on their elected representatives, which seems like a better situation than appealing to facebook to do the right thing.
Republicans are against big government programs.
And Democrats are in tech's pocket.