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Comment by ChrisMarshallNY | Hacker News Reader

I'm writing a fairly basic social media app, right now.

The target demographic is very security/privacy-sensitive, so we have discussions about stuff like this, all the time.

If you block someone, they have no idea, except that you disappear from their radar. Even that, only came about, after a long discussion. Before, blocking someone simply meant that we could not see them, but they could see us.

My location is something that I can force off (meaning that no one can find me in location searches). Even when it is visible, it is "fuzzed," so that the location anyone (other than you) can see, is a random one, within a 10Km square.

All visibility/security is enforced at the server. If possible, in SQL, so it never even makes it into the server code. Having API access buys you nothing.

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> Even when it is visible, it is "fuzzed," so that the location anyone (other than you) can see, is a random one, within a 10Km square.

I hope the implementation of this isn't that I can start sampling your location repeatedly and average them out to find out where you live?

Oh, sure, but it would take a while. The system is not Fort Knox. If someone wants to find one of the members that badly, then there are actually easier ways, outside of the system.

If we decide that it is a concern, I already know how I'd deal with it. I would add a "governor," to slow the process down. Depending on how the location is updated, that could be enough to render it worthless. People can't even see the "fuzzed" locations, unless they are registered members of the community. The locator would have to go through a registered account, and those don't come too easily.

However, if someone is that concerned, they would either hide their location entirely, or not join the community. The app is all about people finding each other.

The standard solution for dating apps is to snap the location to the nearest x kilometer grid point, so that you are losing information rather than simply adding noise

https://robertheaton.com/2018/07/09/how-tinder-keeps-your-lo...

Thanks for that!

Reading it, I'm not so sure it's "standard," as it seems Tinder-specific, but they have done their homework.

I'll have to see what I can do to incorporate something like that.

Just an update: I did a 1Km "snap" to the original location (I basically apply a weighted round to the initial ll), and apply the "fuzz" over that.

I'm sure a dedicated geek could still figure out how to hack it, but our target demographic, despite clamoring for privacy, tends to do Facebook "checkins" all the time.

> Even when it is visible, it is "fuzzed," so that the location anyone (other than you) can see, is a random one, within a 10Km square.

You may want to expand that in lower population density areas. If there's only one little town in that 10km square the fuzzing does almost nothing.

That’s a good suggestion. I’d probably calculate the spread, based on the density of the community members, as opposed to outside stats.

It’s not urgent, at present, but it could be done. See my answer to another point.

Of course you have an idea who blocked, in twitter if you block someone they can’t see your content when you visit their profile. The mute on the other hand just filters from timeline

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