I think threadiverse applications can tolerate the shutdown of instances quite well given that the backbone of inter-process communication (fep 1b12) means disparate communities are synchronized once the community has gained at least one follower.
However, there's room for improvement. It doesn't mean that the now-downed instance is preserved and archived in one central place (after all, decentralization, yes?). Its copies could be scattered all over the threadiverse on different instances, and so gathering them all up could be a herculean task all on its own <img class="not-responsive emoji" src="https://activitypub.space/assets/plugins/nodebb-plugin-emoji/emoji/android/1f613.png?v=17fdcb28ed2" title="
" />
Then there are some instances who have strict content preservation settings. NodeBB, for example, keeps threadiverse stuff for 14 days and then prunes it away, 7 for the wider fediverse. Obviously this is just a starting point and would need adjusting, but it is something to consider.

