Really, a history of likes, a corpus of chat messages, a corpus of public status, and some corpus of potential location data/ usage data depending on the devices used; that's what you liken to an apocalyptic event? Your family, your community, everyone will be just fine. Potentially some population already living in oppressive situations will be impacted (your religious family learns you're gay, etc) but the vast majority will just stop using Facebook and move to the next social media site. What kind of data do you imagine people storing on facebook (remember nothing is there you, the user, hasn't explicitly decided to share with someone aside from whatever they track internally interms of usage and location).
By default a person's friends list is visible from their public profile so if you want to go put together a graph you're welcome to.
First off, yes, I also think people will make it through this and be better in the long run. But I think this stuff is inevitably going to be a major source of heat, and it's going to take some processing. There is a lot of 'potential energy' stored up in private information (I'm not just talking about Facebook). People keep secrets, and the amount being held behind cryptographic algorithms is only growing by the year.
I'm mostly talking about private messages, browsing history, stuff that people would prefer not to be known widely because of pervasive judgements and stigmas in our society.
"What kind of data do you imagine people storing on facebook..."
Nude photos and videos, secrets, accusations, candid personal details, private plans, irrational fears, fantasies, love notes to people who aren't their spouses, etc.
The human web is thickly interwoven. You say "Potentially some population already living in oppressive situations will be impacted". Well, their experiences would not be trivial, and your experience is not disconnected from "those people" either for that matter. I'd imagine they are your friends, your neighbors, your community too. People around us are having secretive relationships ("affairs"), while others hide domestic or sexual abuse. People have skeletons in the digital server closets, things they'd rather forget about and move past, but which are lingering on redundant backups somewhere.
By default a person's friends list is visible from their public profile so if you want to go put together a graph you're welcome to.