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How Facebook's Safety Check Works

highscalability.com

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Re: How Facebook's Safety Check Works

#21

Post by TeMPOraL »

konstruktor wrote: post #14
xxbondsxx wrote: post #13

Earlier quoted context omitted.

If it's any comfort, most people have push notifications turned off for the main Facebook app (understandably since we send quite a few of notifications). However anecdotally some of the survivors of the attacks mentioned that they got phone calls from concerned friends / families while hiding in the Bataclan, which was understandably stressful.

If the safety of your products depends on disabling features, you should stay out of anything remotely safety critical.

What the hell, this can be said about anything. As GP provides an example for, even an unexpected phone call can be unsafe.

Re: How Facebook's Safety Check Works

#22

Post by junto »

jamesfe wrote: post #11
cft wrote: post #10

Incidentally that article implies that Facebook contstantly tracks your geo location even when you do not expressly check in.

We are not OK with the NSA doing this and (theoretically) not viewing the data. We are OK with Facebook doing this and exploiting the data for monetary and market advantages.

Personally I'm struggling to see the dividing line between the two entities. The NSA is a supplier of information for both US corporate interests, the state and the military industrial complex. Facebook is similar except it gets its funding from private equity and advertising revenue, whilst the NSA draws money from the tax payer.

Re: How Facebook's Safety Check Works

#23

Post by tomschlick »

marcusgarvey wrote: post #16
xxbondsxx wrote: post #6

Hey everyone! FB engineer here who wrote the original code for this and gave the talk during @Scale 2015. There's a recording of our talk here: https://youtu.be/ptsCWGZW_P8?t=333 That's a bit more visual and easier to understand. At the end of the day its really just DFS with seen state and selective exploration :)

How does FB decide which disasters qualify for the safety check and which do not?

As described in a post by Zuckerberg, before the Paris attack it was only activated for natural disasters. Paris was the first time it was activated for human disasters and they will be doing it more in the future.

Re: How Facebook's Safety Check Works

#24

Post by twosheep »

konstruktor wrote: post #9

> If you are in an area impacted by a disaster Facebook will send you a push notification asking if you are OK. I guess that's great during an earthquake but can be terrible when you're hiding during a terrorist act.

Most of the trainings that I've gotten for active shooter-type events (gov't employee; they're frequent these days) advises you to silence your phone since the first thing that's gonna happen when the news shows up is everyone is gonna call you anyways.

Re: How Facebook's Safety Check Works

#25

Post by c22 »

chipperyman573 wrote: post #5
Amorymeltzer wrote: post #2

A longer, more involved article from late September has a bit more information: http://highscalability.com/blog/2015/9/28/how-facebook-tells... >If a friend is in the same area then a push notification is sent asking if they are OK. One thing that I'd like to understand is how "area" is defined. The limiting factor is, of course, finding out something has happened, but someone at Facebook has to draw a border that en…

They probably are very generous - I'd imagine the entire country was defined as the "area". The system doesn't work very well if there's false negatives and people don't see it, and if someone sees it but shouldn't all they have to do is hit that they're OK.

I got a safety check because my home city is listed as "Paris", but I was not actually in Paris. I consistently reject requests to share my location though, so it's possible Facebook has more precise information about other users.

Re: How Facebook's Safety Check Works

#26

Post by anandr2013 »

tomschlick wrote: post #23
marcusgarvey wrote: post #16

Earlier quoted context omitted.

How does FB decide which disasters qualify for the safety check and which do not?

As described in a post by Zuckerberg, before the Paris attack it was only activated for natural disasters. Paris was the first time it was activated for human disasters and they will be doing it more in the future.

I think the post had a bit of a frantic working backwards and managing PR tinge to it. A cyclone/tsunami also takes place over an extended period of time, and is very similar to a human disaster.

In any case, it is a really nice feature and the fact that they will start using it for more disasters is undoubtedly a good thing.

Re: How Facebook's Safety Check Works

#27

Post by fnbr »

haraldurt wrote: post #20

>The average distance between any two of Facebook’s 1.5 billion users is 4.74 edges. Sorry Kevin. With 1.5 billion users the whole graph can be explored within 5 hops. Nitpicking here, but that does not follow. Starting from a random user and hopping 5 times in all directions you'd expect to explore about half of the graph.

Your post is technically correct, but I think that you'd be likelier to explore more- say, 80% of the graph. I suspect that there are small pockets of extremely unconnected people which creates a long tail, distorting the mean.

Re: How Facebook's Safety Check Works

#28

Post by omginternets »

tomschlick wrote: post #23
marcusgarvey wrote: post #16

Earlier quoted context omitted.

How does FB decide which disasters qualify for the safety check and which do not?

As described in a post by Zuckerberg, before the Paris attack it was only activated for natural disasters. Paris was the first time it was activated for human disasters and they will be doing it more in the future.

Respectfully, that doesn't answer the question. What is the current policy for determining use?

Re: How Facebook's Safety Check Works

#29

Post by rmc »

omginternets wrote: post #28
tomschlick wrote: post #23

Earlier quoted context omitted.

As described in a post by Zuckerberg, before the Paris attack it was only activated for natural disasters. Paris was the first time it was activated for human disasters and they will be doing it more in the future.

Respectfully, that doesn't answer the question. What is the current policy for determining use?

The real reason, which they probably can't say, is how much media attention it gets in the USA.

Re: How Facebook's Safety Check Works

#30

Post by rmc »

mason55 wrote: post #19
jamesfe wrote: post #11

Earlier quoted context omitted.

We are not OK with the NSA doing this and (theoretically) not viewing the data. We are OK with Facebook doing this and exploiting the data for monetary and market advantages.

Generally people are ok with Facebook doing it because they can opt out. If you notice, the times people really get upset about companies tracking their personal information is if it's either not disclosed or it's done in a shady manner. Also, capitalist societies tend to treat state actors differently than private corporations. It's much easier to choose a new corporation to interact with and the state tends to have…

You can't opt out of Facebook's shadow profiles.
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