This is actually new tech guys, the Homeplug alliance have made great strides in increasing the speed and reliability of using house wire for networking. What Trendnet just did was add wireless access capabilities as well.
DVR manufactures actually have Homeplug built into the DVR's now, so that the consumer doesn't have to run cabling everywhere to get those streaming services to your shiny new HD TV. The technology has finally starting to catch up to real world use.
Bonneville Power has been testing this stuff for bringing internet into a home that has power. This is part of the last mile dream of connecting every home easily to the internet. How many people do you know that still have dialup because there are just outside the CO range for DSL or the cable company's decided to run there lines around some neighborhoods since there were not enough people there to make it worth their time.
The technology has been evolving, it started out slow and a novelty, however it still has more room to grow in speed with many possibility's, such as smart grid homes, used to charge your fancy new EV car when the rates are low, or to keep tabs on how much that old furnace is using electricity and if it is time for an upgrade to save money