What about people who discuss private matters in chat? (e.g. sexuality, medical history, drug use, etc.) Yes, we know that's a bad idea, but most people aren't HN readers.
What about state actors using Facebook's metadata alone to quash democratic movements before they get off the ground?[1] To advertisers, most of the social graph is available only in a semi-abstracted form (e.g. target X, Y, and Z qualities and degrees of connection). A leak or sale could make that information available directly.
What about criminals using a public leak of location data and some predictive algorithms to strategically rob homes? (and maybe also using patterns of likes and connections to predict whose home is worth burgling?)
Really, to say that the valuable part of Facebook is already freely available brings to mind the words "limited imagination." Facebook keeps the valuable part to itself and meters even limited access to it. And there is extensive danger with the possibility of a leak or sale of the raw data.
[1]: https://kieranhealy.org/blog/archives/2013/06/09/using-metad...
What kind of society can handle a full disclosure of information on this magnitude, now or even in the future, looking back? Imagine living 40 years from now, and your parent's full social media records have just been leaked in a mass dump of some data collection company. Could you handle that?
Okay and without appealing to apocalyptic literature, just think about the potentially devastating consequences of mass numbers of people getting access to their enemies' private data all at once. Good for you if you survive that kind of dump personally, but what about your community, your family?
But back to the metaphysical level, shit's about to get real wild if scientific knowledge keeps growing like it has been, especially as "ai" comes more able to translate and interpret these masses of digital data... Plus the vast stores of biological information waiting to be tapped.
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.
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.
And my larger point is not so much about Facebook messages, but about biological data... http://www.ctpost.com/local/article/Yale-study-Brain-scans-m...
Their published data partners: https://www.facebook.com/help/494750870625830
No FB buys third party/offline data about its users, I don't we know what they have:
http://www.bizjournals.com/sanjose/news/2016/12/30/facebook-...