Repeating something I have noted before...I bought and installed a device that deliberately puts pulses on the power lines which supposedly keeps mice out of your walls. (So far I think this really does work, and it is based on some solid research). Anyway, I thought I would need to unplug the thing when I played the audio system. Not so. Evidently the power supplies in my equipment reject this noise (exactly as I would expect them to do). FWIW and IMHO.
High speed internet via electrical power lines
I have been reading that electric companies are going to get into the internet business by carrying digital signals VIA THE ELECTRIC POWER GRID! Essentially, this results in a modulated carrier frequency over all electrical wiring in your house, whether you want it or not! The FCC sees no problems (corporate profits never seem to be a problem for the FCC...note what has become of broadcast radio after deregulation!) and has approved some trials for power companies. Will there be problems for audiophiles from the resulting increased "grunge" on the power lines? Or will this be a non-factor.