The second portion of the post which explains how to capture traffic leaving your device is more informative and probably should have been the main thesis rather than focusing on Foursquare's non-surprising use of constant geo location updates.
(The kind of apps that require a good notification center - like the one in iOS7 - cuz they're spewing so many little bits of suggestions at you.)
I suspect Apple will tread carefully in these waters, but initial signs are worrisome. Let's hope that they can figure out the personal analytics thing and work in some privacy with it too. They're not an ad company, so it's possible. :)