A system for providing wireless telecommunications services to mobile or wireless devices includes data structures and related functionality. One data structure includes at least one location-based services data structure for a wireless device or a user of the wireless device. The location-based services data structure includes first and second data structures representing tables of friends. The first data structure represents a table of friends who may receive a location of the user's wireless device, while the second data structure represents a table of friends who have permitted the user to receive a location of wireless devices associated with them. Various other data structures, functionality and systems are disclosed.