TrackMe is an iPhone app that tracks your location permanently (in the background). TrackMe does not upload the location data to the web, but has an export function that emails a .gpx file with the data using the built-in email program of the iPhone. TrackMe uses very little extra battery, because it only gets notified when you have moved more than 1KM (~ 0.6 miles). Use this application if you are interested in capturing your location data constantly but do not want to share it with the world.

Continued use of GPS running in the background can decrease battery life.