how i solved for this was reciprocal pinning so any node owns all their data (personal log) + whoever they follow (mutual follow reprocity) last x content (indices so its easy to get last n, or last since xyz) and so anyone can decide exactly what they keep or not on their node and thus share by simply following or not (maybe two level, so you can choose to not pin people you follow) heh, smt like that

anyways the idea is very much to do like bittorrent or kademilia but for social media posts i need to research more the fediverse before building anything tho