Fascinating article on how something so simple can be so challenging. Also, potential opportunity for foursquare to sell signal strength data to service providers. Doesn’t violate user privacy since it’s not PII that they’re sharing.
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.