BBC Radio : Should we be frightened of intelligent computers? http://www.bbc.co.uk/programmes/p01rqkp4 Includes Nick Bostrom from about halfway through.
I remember seeing a few AI(and other things, sometimes) debates (mostly on YouTube) where they'd just be getting to the point where they are clarifying what it is that each one actually believes and you get: 'agree to disagree'. The end.
Just when the really interesting part seemed to be approaching! :(
For text-based discussions that fail to go anywhere, that brings to mind the 'talking past each other' you mention or 'appears to be deliberately misinterpreting the other person'
Surely if you provably know what the ideal FAI would do in many situations, a giant step forward has been made in FAI theory?