Are there people who really take this seriously?
In the audio chain people talk about sound waves affected by the cable.
As An Electrical Engineer this is news to me, Sound waves don't propagate down a speaker cable, electromagnetic waves almost at the speed of light do. The only time you will get sound is actually from the speaker not the amplifier or the cable connecting to the speaker.
In the digital audio chain people talk about jitter, temporally accurate rising and falling pulses, and transmission lines.
Maybe if the transmission line is very long and has a high impedance. Actually you can see something like this if you buy a HDMI 1.2 or less cable and try to display 1080p to your HDTV. You would be crazy not to have at the very least a HDMI 1.3 or better cable and cost wise you are only looking at a few dollars, any more than that and you are wasting your money.
In the power supply side people talk about shielding and noise from the power grid.
Yes it is possible to get 50Hz or 60 Hz "hum" (depends on your country) introduced into the audio equipment but any competent manufacture fixed that problem many years ago. Shielding your speaker cable is only advisable if you are next to a high power transmission line and if that is the case I suggest you move.
If anyone is contemplating getting a cable like this I would suggest a HDMI transmitter and receiver instead which IMHO is much more useful. I do think the article suggestion of "snake oil" is very appropriate, still you will find IMO suckers who will buy it.