Some of the details of tbat article fly in the face of what I have observed with wifi, so I googled snoopy to learn more. First thing I learned is that snoopy drones do not fly, although I suppose that could be done.
The gist is that a snoopy station (called a drone) monitors the airwaves and notes what access points wifi devices connect to. All the stations report back device and acces point info to a central location. Access points are then referenced using existing databases. Like Wigl which is built by wardrivers. Once that is done they have a profile of a device and the access points that it uses in the monitored areas.
It's a plausible leap (a flying leap at that) to deploy snoopy as detailed in the original article, although to my knowledge, my devices do not scream out the names of every access point that I have profiled. Even if they did, the encryption would have to match for someone to get in the middle.
Here's a more technical article.
SensePost Blog
This article addresses SSL encryption. Seems the redirect.
The claim that it steals your location data boils down to, it can look up the location of wifi router you connected to. All in all this is the same thing that Google does with their street view cars, which is why google maps can determine your location without accesing your GPS.
edit: I just noticed that the article I linked is two years old.
I would expect that this sw can easily be obtained and by now has been enhanced to address wifi encryption vulnerabilities.