Will cable & internet pollute our power?

A television technician told me that soon the power lines will carry T.V. and internet. Will that add digital hash to our sound systems? What can we do about it?
Broadband over power lines has not taken off as was expected several years ago. However, you can setup your own broadband network using your home electrical wiring today. See this link: http://www.homeplug.org/home/

I use the Belkin 200Mbps devices to connect my PC to a DSL modem in another room in the house. It works great.

I use a SurgeX device to power my AV system and I haven't noticed any issues since setting up the network.
Surge and power conditioning devices definitely filter out these frequencies so that you can't realy connect homeplugs onto the power conditioner or surge suppressor. I use the netgear powerline devices.
There is an enormous amount of garbage on ac lines, with some of it deliberately put there, some by the power companies. There are many devices intended to remove this garbage and some to remove the dc. I have tried over forty of these but have found most do more harm to your music than good. If you install it and let it break in and listen and after a time remove it and you sound improves, sell it. I have found only the Synergistic Research PowerCell stands out in greatly improving your sound.
If power lines and the home circuits could carry radio frequencies why aren't our homes giant antennae nodes on enormous multistate grids ???
I guess dirt is a great dieletric ??
Have you not heard of grounding?