@chjara Back in the Usenet era, the entire history of all NNTP servers can be archived and replayed later, using just a mbox file. You can still read threads from the late 80s as if it was unfolding in real time. Fedi needs something like this.

The privacy situation is entirely different, though. Most Fedi users will probably reject any large-scale, server-wide archives. But I think some preservation can still be done at a smaller scale, for example, archiving posts in one's own timeline or single-user instance for personal use.