Doesn't really matter if he connected to the WiFi: even just having WiFi enabled/turned on means that you should assume every store that you enter knows that you're there, and every other retail store also knows (that you're inside a competitor's store).

There are a number of startups providing these services (some of them have gone through YC I think?). It's now so common that you just have to assume that if your phone is broadcasting anything at all, including looking for a WiFi network to join, that your location is being tracked and sold for competitive analysis by corporations.

Unless there's techniques I'm unaware of, I assume you're talking about MAC address-based tracking? Apple has been working to eliminate that; they've been using randomized addresses during scanning since iOS 8.

The other possibility here is tracking via geolocation or iBeacon, which require an app with location services/bluetooth enabled. And in those cases the tracking is most likely based on Apple IDFA/Google Advertising Id, so you at least have the option to opt out: https://dev.twitter.com/mopub/ui/opting-out-interest-based-a... (assuming the app properly respects the setting).

How much does airplane mode affect this? I have it turned on constantly when I'm out. Mostly to avoid distractions.

Do we know for sure it's working: does that information lead to more sales ?

It's generally understood that it's quite effective to advertise to prior customers compared to say, targeting a geographic area.

Apparently it's about as effective as search ads: http://venturebeat.com/2014/12/16/90-of-marketers-say-retarg...

Yes, this is made possible by WiFi probe requests, which broadcast your MAC address and previously associated access points.

Dont even need to connect. Simply need to find the hardware uid and it can make the connection

Don't have a facebook account, problem solved. They can track you, but they can not make you look at their ads. Ad dollar dry up, so does the incentive to track you.

Better yet don't go to stores that employ this sort of thing.

Chances are good that you have a dozen other apps logging your location as invasive as Facebook is, and those ones participate in the same data exchanges that Facebook does.

There's a strong network of trackers both in the digital space and now the meat space, so the cards are pretty much stacked against you.

When my Nexus 4 eventually dies I'm going to replace it with a dumb phone.

I realised the other day that I use it for the internet about once a week since I'm either at home, work or out doing something where a phone isn't an option (cycling, swimming etc).

>Outside of that, found a social movement that shuns this sort of thing. At the end of the day we are apes that have been herded into these systems without any choice. The only thing to do about it is organize yourself into a group and fight for the reality that you want by shutting out mass society which is out to know everything about you to sell you stuff.

The same could be criticism for most social contracts, and there are groups like the Mennonites who live happy lives with levels of technology they deem fit.

Edit: Why did you edit your comment?

Felt it was too out there.

Facebook still delivers ads on their platform sites, and links your browser (not just cookies) to your identity. FWIW, Google isn't that much different