A mobile device comprising: a location-awareness system configured to track semantic locations of the mobile device, wherein each tracked semantic location is labeled and is a discrete location characterized by one or more identifying observable or ascertainable innate attributes other than geo-physical coordinates and wherein the tracking of semantic locations of the mobile device is based on an ambient radio environment observed by the mobile device; a place manager configured to determine whether a present semantic location has changed so that it differs from a previous semantic location, wherein such determination is based upon the tracked semantic locations; a geo-fence manager configured to: determine whether the present semantic location and the previous semantic location are commonly geo-fenced, wherein such determination is in response to the change; trigger a geo-fence notification in response to a determination that the present semantic location and the previous semantic location are not commonly geo-fenced; and an action manager that is configured to, in response to the geo-fence notification: send a message to one or more predetermined recipients; wherein the mobile device is configured to share route and geo-fenced place definitions with the one or more predetermined recipients based on a private exchange using encryption and authentication protocols. a location-awareness system configured to track semantic locations of the mobile device, wherein each tracked semantic location is labeled and is a discrete location characterized by one or more identifying observable or ascertainable innate attributes other than geo-physical coordinates and wherein the tracking of semantic locations of the mobile device is based on an ambient radio environment observed by the mobile device; a place manager configured to determine whether a present semantic location has changed so that it differs from a previous semantic location, wherein such determination is based upon the tracked semantic locations; a geo-fence manager configured to: determine whether the present semantic location and the previous semantic location are commonly geo-fenced, wherein such determination is in response to the change; trigger a geo-fence notification in response to a determination that the present semantic location and the previous semantic location are not commonly geo-fenced; and an action manager that is configured to, in response to the geo-fence notification: send a message to one or more predetermined recipients; wherein the mobile device is configured to share route and geo-fenced place definitions with the one or more predetermined recipients based on a private exchange using encryption and authentication protocols. determine whether the present semantic location and the previous semantic location are commonly geo-fenced, wherein such determination is in response to the change; trigger a geo-fence notification in response to a determination that the present semantic location and the previous semantic location are not commonly geo-fenced; and an action manager that is configured to, in response to the geo-fence notification: send a message to one or more predetermined recipients; wherein the mobile device is configured to share route and geo-fenced place definitions with the one or more predetermined recipients based on a private exchange using encryption and authentication protocols. send a message to one or more predetermined recipients; wherein the mobile device is configured to share route and geo-fenced place definitions with the one or more predetermined recipients based on a private exchange using encryption and authentication protocols.