Foursquare and other, similar location-based services are no longer merely sophisticated toys that allow users to broadcast their location, but have transformed into real marketing opportunities. Foursquare can also be an important way for teens and parents to always be in contact and aware of each other''s present location. This book introduces readers to all the surprising things that location-based services allow users to do, as well as some of the dangers and pitfalls associated with the technology that should be avoided.