When you launch the Camera app on your iPhone, iPod touch, or iPad for the first time it'll ask you if it can use your location. That uses Wi-Fi router mapping, and, if available, cell-tower triangulation and GPS to determine where you are and record that information along with the photo. In other words ? geotagging. It's great if you want to keep track of where you took your pictures, like on a photo walk or a vacation, but if you want to protect your privacy and keep your location undisclosed, it's not so good. Luckily, even if you allowed location the first time, you can change your mind at any time.
Full story from the iMore Blog...