>> You know what is offline-tolerant? NNTP and email.
Imagine a distributed social network where updates come via email. Updates are identified by the email client (or other) and automatically sent to whatever program needs to process them. You end up with a local copy of everyones stuff that is kept for a period of time.
I have been working on idea for generic store-and-forward messaging. Basically, email for everything. The idea is that store-and-forward is more reliable when there are limited or no network. It would also work well for interplanetary communication.
For some applictions, it is simple to fallback or use always and luckily the basics are included. Unfortunately, lots of applications won't work at all and many would have to be rewritten.
Why is this website hosted in Russia (given current geopolitics), and why does this website have a certificate issued by ca.cypherpunks.ru instead of say Let's Encrypt?