I think there is two ways to consider ambiguity :
Way 1. Subjects are ill-defined, everything is fuzzy, nothing can be asserted for sure.
Way 2. Subjects are well defined, but in many ways, as so many views in/from different frameworks/perspectives.
Way 1 is good for unformal and cheerful conversation, like the one you used to have in forums, and now blogs, RSS, tagging and the like. But it is IMO pernicious : people either think they agree, though they speak passed each other, or the other way round think they disagree because they have no way to figure if they actually have different viewpoints, or if they speak about different things. Billions of examples available everyday.
Way 2 is what TMRM and hubjects are about : subjects are ambiguous, contradictory, fuzzy, moving targets, OK. But each view on a subject has better be well defined, and the rules for this definition explicit (perspective disclosed). You know your view is not exhausting the subject, you can explore different views, see if their logics are compatible, if they can play nicely with each other or are too orthogonal for that etc ... So you can agree that you agree or disagree on clear grounds, and go to war if needed, but with crystal clear reasons.
I jumped on this thread on Forthcoming blog, after a similar exchange with TMRM folks on the same subject of ambiguity. It is deep down in the comments, so here is the quote.