As I have been known to wonder off aimlessly following the front wheel of my motorcycle it can be comforting for Herself to know I am not in the ditch somewhere. There are many tracking devices (Spot being one), but that can get expensive. A few minutes with Google showed me how to make my location known to anyone I choose, for a period I choose.
To activate this I followed these steps outlined here. Herself received an email advising her of the link to a google map which shows my location in real time. This remains active as long as I leave the service turned on and is without cost.
As google already knows all there is to know about us I am unconcerned about this additional information. It was this article that got me thinking about this. 1984 is now.