that it has taken this long for a power supply manufacturer to build in Ethernet over power lines into one of their PSUs, but Cooler Master was showing off a 700W unit that does this. Now it might not be the most elegant solution, but at least it removes the need for another wall plug.
The idea is that you use one of the standard Ethernet over power lines adaptors next to your router and connect this with a network cable to the router. The power supply then picks up the signal from the adapter next to the router. The slightly quirky bit here is that Cooler Master decided to put an Ethernet port on the rear of the PSU, so you'd have to attach a cable to it and connect it to the Ethernet port on your motherboard.
We'd like to see an implementation that offers a built in USB Ethernet adaptor instead which connects to one of the USB headers on the motherboard inside the case to reduce cable clutter, but at least this is a step in the right direction for the Ethernet over power lines technology.