Don
While I still think that USB cable is snake oil I used to say the same thing about HDMI cables until found out I was wrong. The cable can impact the 0's and 1's normally due to bandwidth and distance and I have come across super cheap USB's that corrupt the 0's and 1's.
It can corrupt the stream of 0's or 1's (in the same way a poor quality HDMI can), e.g. in a very simplistic explanation - dropping 1's may create audible "gaps" of silence in the track, whereas as 0 corrupted to a 1, may add audible "pops" or other unexpected noise.
What it can't do however is modify the 0's and 1's in such a way that the resulting sound is "more natural", as that would require altering the whole of the bit steam.
However I'm waiting for st!xt to explain how he thinks this is possible