From near the dawn of electric power we had electromechanical utility meters  that had to be physically accessed and manually read. Those were replaced in the mid 1990s with Automated Meter Reading (AMR) meters. AMR meters wirelessly report our readings to the utility’s radio van as it drives through our neighborhood to collect readings without the driver having to get out.  Such meters are one of two types:
A “Wake-Up” meter reports its reading when prompted by a signal from the utility’s passing vehicle. Such an arrangement is a form of RFID similar to how an EZ-Pass transponder responds when “interrogated” by an electronic reader at a tollgate, for instance. A “Bubble-Up” AMR meter transmits its current reading constantly around-the-clock regardless whether it was prompted or not.

What is a “smart” meter and why does it matter?

Not to be confused with parking meters, Smart Utility Meters report our electrical power usage wirelessly in real time back to National Grid on a 24/7 basis. Smart Meters, or Advanced Metering Infrastructure (AMI) meters are a refinement on AMR. AMI meters communicate continuously with the utility through neighborhood collectors that consolidate and report readings wirelessly to substation collectors, etc. eventually reaching the company. Smart Meters communicate with neighborhood collectors over the 902-928 Mhz ISM band where a full 1 watt of transmitter power is allowed  compared to the 100 milliwatt maximum power allowed for typical Part 15 devices like cordless phones and wireless microphones.