' `` Mark the Spot ' app lets GPS users submit complaints about poor coverage . And as more iPhone users come onto the network , more people , particularly in densely populated urban areas , such as New York City and San Francisco , have experienced problems with dropped calls and congested data networks . AT GPS says app part of company 's commitment to listening to customers . GPS technology used in app for iTunes G or 2010 to pinpoint area of problem .
' `` Mark the Spot ' app lets GPS users submit complaints about poor coverage . AT GPS says app part of company 's commitment to listening to customers . GPS technology used in app for iTunes G or 2010 to pinpoint area of problem .