From www.machinadynamica.com/machina41.htm
Quote:
The Clever Little Clock does not plug into the wall and has no direct or indirect influence on the audio signal -- not on house wiring, audio components, cables, interconnects, power cords or acoustic waves. Yet the Clock has a pronounced affect on the sound we hear from all digital and analog playback systems.
OK folks, I knew you were waiting for this, so I'm going to tell you why these work.

It has to do with psycho-acoustics. Since, according to their web site, this item has no influence over the signal, components or acoustics, then, if it has any effect, it must be in the psycho realm.

So the reason this works for some people is that:

Some people will believe anything.