A (hopefully brief) attempt at responses -- I'm working on a more detailed one.

Q: How should platforms approach keeping terrorists from spreading propaganda online?

Briefly: consider this from an epidemiological perspective. There are infectuous agents, hosts, and vectors of propogation. In public health, a combination of factors is used to limit the spread of disease, with exceedingly high effectiveness. With greater effectiveness than all of acute and therapeutic medicine, by a factor of about 85% to 15%. See Laurie Garrett's The Coming Plague.

Monitoring, innoculation, disruption, containment, elimination of breeding and development conditions, and avoiding strengthening resistance to treatment* are all core elements.

The question of whose terrorist is whose freedom fighter also arises, as do questions over acceptable and unacceptable tactics in various forms of warfare.

Q: After a person dies, what should happen to their online identity?

This would be a very good thing to make a determination of whilst the person is still alive.

There is considerable prior art, on which I strongly recommend researching the legal definition and practice of will.

There's also a practice amongst librarians and academicians of access to personal writings, journals, etc., with consideration for both the deceased and those still living who might be affected by revelations.

Q: How aggressively should social media companies monitor and remove controversial posts and images from their platforms? Who gets to decide what’s controversial, especially in a global community with a multitude of cultural norms?

Cultures vary tremendously in norms, and in what is considered acceptable or transgressive. Communications, online or otherwise, breaks down the barriers between such cultures.

One possible response is to perhaps resurrect at least some of those walls, at least in part. There's a notion from travel, "when in Rome...". There's also a trope of travel, of the ugly tourist -- British, American, German, of late, Japanese, Chinese, or Russian. Issues extend to both the traveller and the native.

The dislocation of online space in violating a sense of "whose space is this" is a severe one. That was amongst the more toxic elements of Google's exceedingly ill-conceived Anschluss of Google+ and YouTube. Not only were privacy norms (enshrined only a few years earlier in YouTube's own privacy guidelines) violated, but members of each community found themselves overwhelmed by "intruders" from the other.

De-globalising the community would seem a partial response.

Q: Who gets to define what’s false news — and what’s simply controversial political speech?

Briefly: Someone who's exceedingly good at it. And reasonably unbiased.

Non-briefly: this is among the fundamental philosophical dilemmas. There is considerable prior art, there are authorities, they should be consulted (and questioned). This is not a greenfield. Making a list of those authorities and references, sharing it, and the discussion, should help.

Epistemology, justice, the Scientific Method, the history of science (and where it has and hasn't succeeded, and at what rates), the history of free expression (and the limits placed upon it), including J.S. Mill (who did NOT coin the expression "the marketplace of ideas", that was a free-market advocate, Francis Wrigley Hirst), and more.

Q: Is social media good for democracy?

Wrong question.

Every single change in communications and media has had profound impacts upon, and fundamentally changed, the societies in which they occurred. See Elizabeth Eisenstein, Marshall McLuhan, and others who've written on the social impacts of communications. And by every, I mean going back to speech itself, as well as writing, clay tablets, paper, print, radio, film, phonograph, television, the Internet, and mobile.

Facebook has to face the fact that it and Google are the two largest media institutions in all of history. Their reach is on the order of billions of people. Contrast with the most-published books ever: a few billion for the Bible and Mao's Little Red Book, 500 million for Don Quixote. By contrast, "Gangnam Style" has been viewed over 2 billion times on YouTube alone.

That is great power. Spider Man on line 3 with a word about responsibility.

Social media is going to change democracy. Full stop. It may end it. It may only interrupt it, as radio did in spurring on fascism. We want to look to history, psychology, sociology, anthropology, economics, communications studies, information theory, and more, to get a sense of where the hell this is headed. Of late it's been more than a bit concerning.

Q: How can we use data for everyone’s benefit, without undermining people’s trust?

Wrong question. It presumes the answer, then poses the question.

Briefly: 1) respect people's boundaries, generally and 2) consider the public welfare, overall.

Non-briefly: this is among the fundamental philosophical dilemmas. There is considerable prior art, there are authorities, they should be consulted (and questioned). This is not a greenfield. Making a list of those authorities and references, sharing it, and the discussion, should help.

Q: How should young internet users be introduced to new ways to express themselves in a safe environment?

Not solely by a party whose self-interests fail to align with those of the young. Which would exclude Facebook, amongst other present Internet Giants: FAAMG -- Facebook, Amazon, Apple, Microsoft, Google.

The risks of indoctrination at a young age are exceedingly great. This is a role I'd like to see placed outside the control of any of the major participants to the extent possible.

Again: a partial response. There are questions not being asked by FB which should be, and much more which might also be said. I see serious limitations to this approach, and will be voicing criticisms.

But for all that, I applaud the initiative and approach, and hope that it evolves into an exceptionally necessary discussion. Facebook have out-shone the other principle participants in this space, and I truly hope they step up to the challenge.

I've alluded to prior art and works. In 2015 I suggested on a G+ thread that Google compile a bibliography or syllabus, make it required reading of all employees and contractors, and share it with the public. I'll extend that suggestion to Facebook as well.

https://plus.google.com/+YonatanZunger/posts/cKot7AKmtty