http://calendar.perfplanet.com/2010/the-full-stack/ →
Well-written article by Carols Bueno (who works for Facebook) describing how a full-stack programmer would approach thinking/reasoning about a large-scale system (in this case a web application but this sorta thinking can be applied to reason about any system).
Acquiring full-stack experience & knowing the internals of everything is immensely powerful when designing systems. You probably cannot master everything but I have started noticing that once you know the internals of a bunch of systems, you can very quickly guess how something else might work internally. You begin with a handful of potential guesses and then rule out wrong ones by some quick experimentation/hacking.
