Modern cameras include GPS data in photos, and software like iPhoto and Aperture uses this data to provide location info for features like Places. Not only are many people unaware that GPS data is included in the pics they’re taking, but uploading these pics online means that the world knows exactly when and where they were taken.
Apple’s professional photo Mac software, Aperture, is supposed to let you strip location data from your pics before you share them from the app. The problem is that the feature doesn’t exactly work in the current version of Aperture.