There is local towers that are downloaded so that gps can find you in seconds rather than minutes. Every app that uses location data wont work until you tell it its okay to do so. The data people found is for the phone to quickly find where the towers are around you, it is not a list of where you have been, other than the 100 mile rack us around you.
http://www.apple.com/pr/library/2011/04/27location_qa.html3. Why is my iPhone logging my location?
The iPhone is not logging your location. Rather, it’s maintaining a database of Wi-Fi hotspots and cell towers around your current location, some of which may be located more than one hundred miles away from your iPhone, to help your iPhone rapidly and accurately calculate its location when requested. Calculating a phone’s location using just GPS satellite data can take up to several minutes. iPhone can reduce this time to just a few seconds by using Wi-Fi hotspot and cell tower data to quickly find GPS satellites, and even triangulate its location using just Wi-Fi hotspot and cell tower data when GPS is not available (such as indoors or in basements). These calculations are performed live on the iPhone using a crowd-sourced database of Wi-Fi hotspot and cell tower data that is generated by tens of millions of iPhones sending the geo-tagged locations of nearby Wi-Fi hotspots and cell towers in an anonymous and encrypted form to Apple.
4. Is this crowd-sourced database stored on the iPhone?
The entire crowd-sourced database is too big to store on an iPhone, so we download an appropriate subset (cache) onto each iPhone. This cache is protected but not encrypted, and is backed up in iTunes whenever you back up your iPhone. The backup is encrypted or not, depending on the user settings in iTunes. The location data that researchers are seeing on the iPhone is not the past or present location of the iPhone, but rather the locations of Wi-Fi hotspots and cell towers surrounding the iPhone’s location, which can be more than one hundred miles away from the iPhone. We plan to cease backing up this cache in a software update coming soon (see Software Update section below).
5. Can Apple locate me based on my geo-tagged Wi-Fi hotspot and cell tower data?
No. This data is sent to Apple in an anonymous and encrypted form. Apple cannot identify the source of this data.
6. People have identified up to a year’s worth of location data being stored on the iPhone. Why does my iPhone need so much data in order to assist it in finding my location today?
This data is not the iPhone’s location data—it is a subset (cache) of the crowd-sourced Wi-Fi hotspot and cell tower database which is downloaded from Apple into the iPhone to assist the iPhone in rapidly and accurately calculating location. The reason the iPhone stores so much data is a bug we uncovered and plan to fix shortly (see Software Update section below). We don’t think the iPhone needs to store more than seven days of this data.