Just read that on the engadget site
http://www.engadget.com/2011/04/20/researchers-find-ios-4-records-your-location-in-system-file-syn/

Why is it that these companies insist on "tracking" its users and then hide behind the "Terms & Conditions" ?

Not sure if this uploads in any sort of real time which could be useful for finding lost friends/family members etc