Thanks to CoreLocation in the iPhone SDK, Apps can make use of WiFi, Cell, and A-GPS (for the iPhone 3G) information to keep track of where you are. Your Twitter feed can be tagged with your current location, or can show you just those contacts in a certain vicinity. A movie app can automatically fetch show times for all the theaters in a certain radius. A to-do app can pop up location-based (rather than just time-based) alerts, reminding you to help your mom change a lightbulb next time you're there, or ping you when you pass the electronics store so you remember to pick up that cable you need.
Convenient? You bet. Powerful? A game changer. Invasive? Er... Could certainly be.
What if you don't always want whereabouts broadcast, if you don't want everyone to know (or potentially be able to find out) where you are, when you're out shopping, where that picture of your child was taken?
Read on to find out how apps ask for permission to use your location, how you can change your mind and make them ask you again, or how you can turn off location services completely.