Thanks to Ward Cunningham, the metaphor technical debt is quite a well-understood concept. It means you are borrowing  time by writing messy code, not worrying about scaling, documentation or other items required for a quality release. You go quick and dirty to release early but all that bad code will incur debt. And there will be a time when you need to pay that debt back - with interest.

I think the parallel with the product design world is a welcome addition. I frequently find myself using the term product debt but I also get the sense that very few people know what I am talking about. Like technical debt, product debt is inquired when you make short term product decision with an expensive long term consequence.