I remember finding this a very interesting read when it first came out. It's clearly colored Sussman's research for the years since, for example his work with Alexey Radul on "propagators".<p>However, I've never found a way to make it actually work in a real system. The cost of redundancy is high, and you absolutely need a way to pass around the chain of configuration choices with the values. Otherwise, if something goes wrong, or even to understand the values you're getting, you're stuck grubbing through log files (if you're lucky) to find out what happened.<p>I suppose his propagator research is a way to make this easier to do, but it's so specialized that it becomes an all-or-nothing approach, not something you can incrementally develop towards.