working toward a rigorous definition of 'continuous mixing'

So I have been thinking about this idea of continuous mixing, or generally speaking, more content aware automatic song to song transitions for some time now. To that end I'm aiming to put something together for DAfX on the topic. As this deadline for submission is fast approaching, my writing is generally focus in that direction. In the meantime however, I'll throw out a vague english definition of continuous mixing so that you the reader can get an idea of where I'm coming from on this topic, with some more rigorous definitions to follow.

continuous mixing: A song to song mixing technique where the goal is to obfuscate the transition between the two songs such that a casual listener cannot immediately pinpoint when the transition occurred. This can involve the use of beat matching/alignment, phrase matching/alignment, content aware equalization and other technical elements as well as sensible song selection with regard to harmony (i.e. key changes that make musical sense).

So that's my starting point. Anyone else have an opinion? What is continuous mixing mean to you? Bonus question! When is continuous mixing an appropriate transition technique in playlist presentation? I'm starting with modern electronic dance music, but these techniques can certainly apply to other musics (speed metal? maybe. free jazz? probably not...)