
The Hack That Brought Foursquare Back From The Dead - JoshTv
http://www.wired.com/business/2013/12/the-brilliant-foursquare-hack/
======
raldi
To save you some reading, the crux of the hack is to consider a weak GPS (etc)
signal not as a lack of data, but rather as a source of data in itself: the
fact that the GPS signal is weak tells you something about the user's probable
location.

~~~
justinsb
Isn't this exactly how location is always done without GPS? Look at the
strengths of all the radio signals we can see, and match against known
locations? Admittedly it's previously been primarily cell-towers & wi-fi, not
GPS signal strength, and I thought most of the previous data had been
collected by people that also had GPS, not via foursquare checkins...

If not, why does my Android phone ask me to turn on wi-fi to enhance location
information?

Edit: To answer my own question, the Android source code for this used to be
available. At the time, they passed the visible wi-fi SSIDs and the cell-tower
IDs, but not the signal strength (they had it in both cases). Not sure why
they didn't pass the strength. Maybe it made caching really hard; maybe it
sufficed just to pass them in order; maybe it didn't make a big enough
difference...
[http://www.netmite.com/android/mydroid/frameworks/base/locat...](http://www.netmite.com/android/mydroid/frameworks/base/location/java/com/android/internal/location/LocationMasfClient.java)

To me, this actually raises more questions. It's so surprising to me that
Google don't pass the signal strengths ("everyone knows" that is how
triangulation works), that I'm thinking the real secret is that the signal
strength isn't actually helpful. In other words, I'd bet Google tried what
FourSquare have discovered, and rejected it. Or it's patented :-)

~~~
mutagen
The primary purpose of WiFi to enhance location information is to bootstrap
the download of current GPS orbits (the ephemeris) [1].

More advanced techniques relying on radio signal strengths, RTT time, and
other observables [2] are being developed but I don't know of any in
widespread use. I wouldn't be surprised to see something emerge soon though.

[1]
[http://en.wikipedia.org/wiki/Assisted_GPS](http://en.wikipedia.org/wiki/Assisted_GPS)

[2] One example: [http://ws2.binghamton.edu/fowler/Improving%20WLAN-
Based%20In...](http://ws2.binghamton.edu/fowler/Improving%20WLAN-
Based%20Indoor%20Mobile%20Positioning%20Using%20Sparsity.pdf)

~~~
JangoSteve
Google actually does collect wifi location data via Android devices. There's a
setting that allows you to toggle this data on/off. If you turn it off, it
actually disables the course location API available to Android apps (I
recently encountered errors with both the Lux and the UCCW Android
applications due to the fact that I had this setting disabled and those apps
_only_ had course-location built-in).

Now whether Android actually uses the wifi data to determine location, as
opposed to simply collecting it and manually disabling course-location if you
don't send them wifi data, I have no idea. It does seem to be related though
to the new Geofencing API available in the latest versions of Android.

EDIT: Sources!

[http://www.zdnet.com/blog/networking/how-google-and-
everyone...](http://www.zdnet.com/blog/networking/how-google-and-everyone-
else-gets-wi-fi-location-data/1664)

[http://developer.android.com/training/location/geofencing.ht...](http://developer.android.com/training/location/geofencing.html)

------
mintplant
> Foursquare already had a massive database of check-ins — location
> information about the places its users most liked to go. And this data
> didn’t just include the place where someone had checked in. It showed how
> strong the GPS signal was at the time, how strong each surrounding Wi-Fi
> hotspot signal was, what local cell towers were nearby, and so on.
> Leveraging this data meant that Foursquare could still grab a good current
> location even if users were underground, near a source of radio
> interference, or facing some other signal obstacle. Chances are, some prior
> Foursquare user had seen the world through the same flawed eyes and reported
> his or her location.

This sounds more valuable as a technology than the social network side of the
business itself.

If another company wanted to build up a similar database of location
information, they could send out a fleet of its own staff all over the world
to collect it, à la Google's Street View cars. But Foursquare has managed to
sidestep all of this expense and infrastructure by harnessing its userbase as
a massive, free source of data input.

Through badges, recommendations, and deals with local stores, they've created
an incentive to provide the data they need. And through the mechanisms they
have to prevent cheating in the game side of things, they've accidentally
developed a way to ensure the accuracy of the location information their
system can provide.

Licensing out this technology could become the long-sought-after profit engine
for Foursquare, paying the bills for the flashy social network layer on top
that keeps the data flowing in.

~~~
mseebach
>> It showed how strong the GPS signal was at the time, how strong each
surrounding Wi-Fi hotspot signal was, what local cell towers were nearby, and
so on

That quote struck me as very strange. Why would they collect all that data in
the first place, anyway, if not to do exactly this?

~~~
mintplant
Foursquare has measures in place to prevent people from gaming the check-in
system--to keep people from faking check-ins and gaining badges and mayorships
that they didn't earn. From what I've gathered, they collected this
information originally to prove that someone was really at the location where
they claimed to be.

~~~
VLM
"to keep people from faking check-ins and gaining badges and mayorships that
they didn't earn."

And yet, people claim bitcoins are worthless.

------
austinl
A bit of background - "geofencing" has been around in iOS as part of Core
Location since version 4.0. Given latitude and longitude, you can pass in a
radius and create a circular region (or specify a set and create a rectangle),
with callbacks that trigger when the user enters or exits that region.

One of the main points in the article is that it's particularly battery
intensive to update the user's location, so there's a trade off between
accuracy and battery usage. To try and solve this, Apple created a hierarchy
of accuracy constants, which range from "best" to three kilometers, but it's
only somewhat effective at preserving battery life.

The other strategy is monitoring "significant changes" in location, based on
cell towers/wifi signals. For this, Apple provides a method called
"startMonitoringSignificantLocationChanges" if your app needs to constantly
monitor the user's location.

From what the article said, Foursquare is trying to improve these methods by
creating probabilistic maps so they can draw better regions for each user, and
therefore check for location updates less frequently. I'm assuming there are
similar methods for Android.

Here's the documentation for one of the main classes in Core Location called
CLRegion:
[https://developer.apple.com/library/ios/documentation/CoreLo...](https://developer.apple.com/library/ios/documentation/CoreLocation/Reference/CLRegion_class/Reference/Reference.html)

------
drakaal
Summary: FourSquare is moving from a checkin service to doing positioning data
at higher accuracy and lower power based on big data.
[http://www.skyhookwireless.com/](http://www.skyhookwireless.com/) does the
same thing. Maybe not as well, but generally the same.

------
GrinningFool
foursquare is still around?

Hyperbole aside, I thought foursquare was an excellent idea - and if more
businesses around me used it, I"d probably still be using it myself. (Reading
the article, it seems that if you live in NYC or SF it's a lot more useful
than it's been to me.)

As it is, I think the last time I even looked at it was nearly six months ago.

~~~
protomyth
"if you live in NYC or SF it's a lot more useful than it's been to me"

It seems like services that bring people from vast geographic distances (e.g.
Facebook, Twitter) have a longer life than services the geo-limit the
audience. If you're in NYC, SF, or LA, geo-limited services work due to
density, but you the threshold seems to dive after a couple of cities down the
list. Color was the ultimate example for me on something that was so geo-
limited that I couldn't imagine it working.

~~~
hnriot
It's the density that make Foursquare more popular in SF and NYC but rather
the demographics of those areas, modern, high tech centers of urban
sophistication. The fly over states are more concerned with the latest
developments in pickups and gun racks to care much about checking in at the
hottest espresso bar.

~~~
frogpelt
While it's true that people in rural areas often don't care about the same
things that people in big cities care about that doesn't mean they are
oblivious or opposed to new technology.

I have a friend who is a commercial poultry farmer in rural Mississippi. He
can turn on his chicken house feeders from anywhere in the world with a smart
phone app. Some of the coolest technology being built is farm-related. People,
no matter where they live, just want technology that makes their lives better
in some way.

~~~
tedunangst
_People, no matter where they live, just want technology that makes their
lives better in some way._

But they are different than the people who just want technology and see it as
its own end.

~~~
protomyth
"But they are different than the people who just want technology and see it as
its own end."

Those people exist everywhere including the non-costal states. Long winters
clear a lot of time for technology exploration.

------
hendzen
Another year, another Foursquare pivot.

------
untog
This problem isn't solved yet. For me at least. I turned on the passive
notifications, and they started going off when I was traveling on above ground
sections of the subway. Or when I got out by my office.

So I turned them off. Somehow Foursquare needs to crack working out when I
want those notifications and when they're irrelevant. They should have enough
data to do it.

~~~
lnanek2
Yeah, I've been using 4sq for years and still do, but just don't have any use
for the passive notifications. They only crop up when I'm going somewhere or
doing something already. Most amusingly, they've been showing up on flights
lately and they are actually correct. Not sure how that even happens since I
know Google's WiFi database tends to just have the wrong location for train
and plane WiFi in my experience. I'll hop on a train in NYC and it will say
I'm in Boston.

~~~
gky2
I've actually never used Four Square myself but I saw a lot of people use it
back in the day... This new feature seems like just the stepping stone for
them to implement what they really want, so hopefully in the near future it'll
process the type of data you two have mentioned here.

------
schnevets
I always loathed Foursquare because it interfered with social occassions. You
and some buddies walk into a location, and suddenly everyone has to take out
cell phones. It's relieving to hear that the company's strategy was always to
become less obtrusive. I may actually download the new app now.

~~~
lnanek2
I've actually found it to be a social benefit myself. Most of the people I go
out with use it and we tend to compete and discuss what picture and tagline
we're going to use and who is better and who checks in first. Much of the time
the conversation later goes on to what cool things our friends did lately or
if we can tell it is snowing somewhere better through 4sq or Instagram, often
with much showing of the phones to each other.

I guess younger generations build technology into their lives whereas for
older people it is just an interruption. Try just friending everyone
everywhere you go and eventually you'll have cool people all over the world
doing fun things that can start conversations instead of stop them.

~~~
VLM
"I guess younger generations build technology into their lives whereas for
older people it is just an interruption."

I hardly speak for every obsolete senior citizen over the age of 25, but its
more of a perception of what is good or bad taste rather than neo-amish-ness.
Social etiquette. For any elderly geezer over the age of, perhaps, 30, walking
into a social occasion and ignoring the meatspace people to instead play with
a phone would be considered intentionally highly insulting. If gentlemanly
behavior means always doing everything possible to increase the comfort of
those around you, which is a reasonable short definition, ignoring people to
play on the phone doesn't score very high.

------
morganb180
The notification fatigue is going to set in. Not sure this is a sustainable
growth lever.

------
antr
On Europe and Foursquare: is it just me or their data quality in Europe is
really weak?

A couple of weeks ago I tried using an app that uses foursquare's API and I
couldn't find 4-5 restaurants in London I wanted to tag/save (each time I was
sitting at the restaurants in question). Instead I had to use Google Maps to
save the location of these places, otherwise I couldn't of done so.

------
lucb1e
Page is blank when adblock is enabled. Anyone else having this problem?

I just won't read this article now. Not my problem.

~~~
protomyth
Using Safari with ad blocker and I can see the content.

I really didn't want to install an ad blocker but the damn pop-ups were
getting too much.

~~~
GuerraEarth
Even worse are the audio ads.

~~~
protomyth
No doubt. I wonder how many people have the sound off on their computer's
until they actually need to hear something?

------
yason
Funny enough, I prefer to disable any existing notifications so that I can
walk about or sit around undisturbed. (SMS and phone calls are ok, but mostly
because I get them so rarely and if I do they actually might be important.)

------
coob
I wonder if they're going to start using the M7 in the 5s for even more info
that will help with this.

------
jgalt212
Has anyone ever read an article on Foursquare without a picture of Dennis
Crowley in it?

