I am in a way arguing semantics because I believe its confusing to non EE people reading this to use a term like 'phase cancellation' in a way that is very different from its usage in almost every other context. In general it refers to the sum of two waves equaling zero (or some reduced value), i.e. destructive interference. In this case the opposite is happening and the vocals are removed not due to a sum of the waves but rather a difference equating to zero.
Yes, we have interacted there a few times. I would probably use the term "common-mode cancellation." But it is something that is a very base concept in EE and the other terminology makes sense to me, although for non-EE I could see the issue.
You should make hacker news your website on EE? Your account looks some bare there, add some information!
Side note - welcome to hacker news! Assuming your the same kortuk from the EE stack exchange I believe we've interacted a few times. My account there is: http://electronics.stackexchange.com/users/1438/mark