Yes, an address is the unique identifier for a location within a city, and should let everyone know exactly where you live, but how useful is it? How are addresses determined and what do they mean? Most addresses include a north/south/east/west coordinate. North, south, east or west of what? Are all addresses based on one central coordinate in downtown Phoenix, or does each city have their own coordinate sytem? How much do we really rely upon an address to arrive at a destination? If you know the answers, congratulations; if not then read on.