[keithnz]

this article takes the metaphor way too seriously. At best, this is language we can use to help clarify what things we need to focus on and the trade off, most often useful when describing things to non technical people. At worse, it can be taken in such a way that we try to quantify the debt so it can be seen how badly things are screwed up. Its not a metric and doesn't really have a strong definition, it's more conceptual.