From the New York Times:
Back in the Stone Age of home networking, anyone who wanted to play on a computer not hooked directly into an Internet connection had to snake phone lines or Ethernet wires across floors and up staircases.
People talked about a promising idea: using the electrical wiring already in the house to move data from room to room. One early application, the X10 system for controlling lights and appliances, didn’t always work well. The technology was certainly not ready to be used to bring Web pages to computers anywhere in the house.