Good point. There's some good discussion in the Rails community about ports-and-adapters architecture around that theme. Matt Wynne gave a talk at goruco this past year on the subject that's worth checking out: http://www.confreaks.com/videos/977-goruco2012-hexagonal-rai...

I was using the analogy of the composability of Unix tools as a role model for how to think about the segregation of roles in an object-oriented system. I agree with you that the ways in which we can couple these objects together through their interfaces is the core of what we're designing. I think this philosophy as an analogy (especially as outlined by ESR) is applicable to a wide variety of things beyond even programming. Interesting to think about, anyway. Thanks for your thoughts.

Thanks for the feedback! Currently links are only shown chronologically. There's a tag mechanism that surfaces the links by topic. Agreed that it could get noisy - likely though that could be helped by allowing people to create their own custom pools of topics and people.