Allows you to connect your devices to the internet via your home power sockets. Providing you with wired (i.e. quicker) home network.
Handy if you have an whole array of equipment connected to your TV for instance (Home theatre PC, consoles, media streamers, internet-enabled TVs and set top boxes, Blu-ray players etc)
"Instantly create high-speed, wired network connections to seamlessly stream your high-definition media to your connected home theatre and gain fast, reliable access to the Internet. WD Livewire powerline AV network kit extends the Internet to any room using your homes electrical outlets. Stream the highest quality HD video, play games, and transfer files within the home or over the Internet using secure and reliable high-speed connections. Get the performance of a wired network without running wires.
Simply plug the adapters into your electrical outlets to create a high-speed network connection anywhere in your home. No tools needed. No holes in your walls. Media-optimized HomePlug AV technology offers up to 200 Mbps* performance for smooth HD video streaming over your network. A total of 8 ports means you can connect up to 7 devices and your router, all protected with 128-bit encryption."
The benefits over existing over-power Ethernet adaptors are having up to 4 ports (or three + the router, at the router's end) utilising an single socket per adaptor.
Again, it's new (or at least updated) technology - so please bare that in mind before voting, if you have had a negative experience with the tech or the supplier then please do share - thanks.
A review can be found here;http://www.reghardware.com/2010/09/28/review_networking_powerline_wd_livewire/
the official Western Digital product page can be found here;http://www.wdc.com/en/products/products.asp?driveid=861