Pardot has partnered with Rapleaf, a leading provider a social profile data to augment prospect records with information from their publicly available networks (LinkedIn, Twitter, etc.). While not all of your prospects will have available social data, it is likely that a good portion will. This will allow you to infer location, job title, etc. — automatically.
If for some reason you do not want this functionality, you can turn it off by deleting/disabling the Rapleaf connector in the administration section of Pardot.