Yes, Broadband Over Powerlines (BPL), HomePlug, IEEE P1901, etc. have been around for many years. It's used in Europe & Asia, and slowly being adopted in the U.S.A. I've installed & use Panasonic BL-PA100KTA HD-PLC Ethernet Adaptor BL-PA100A units.
answered Jun 10 '10 at 07:33
As safe as electricity can be. If your neighbours have the necessary equipment, they can read the electromagnetic radiation emitted by your screen... but in normal circumstances, your neighbours shouldn't be able to pick up the signal unless you're sharing a fuse box.
answered Jun 10 '10 at 05:05