iOS, Keeping track of your whereabouts, Frequent locations

iOS location services

iOS 7 keeps a track on where you hang out most, allowing it to cache relevant nearby data. Once you’ve used iOS 7 for a while, go to Settings > Privacy > Location Services > System Services to view a list of where you've been most. Near the bottom, you’ll see a place to tap that groups your locations into areas. Tap on a specific region and you’ll get a map with all the places your iPhone has recorded a location. If you are worried you can turn this feature off in the same place.

Pro's: iOS cached data like maps and local information, so you'll find relevant stuff, faster
Cons: When you have Privacy concerns..
Maybe you'll want to switch of the Location-based adds.