So this question will get technical – eventually – but first check out Hanselminutes with Atwood (et. al.) where Scott basically invites developers to try to hack this site. It’s a hoot. I first thought (out loud of course, because with headphones on you get the best stares from people as you think out loud) “he either just got off a plane without meal service from Hong Kong or was ticketed for driving a Bobcat after too much cough syrup.”
So the question is, if a site like this can survive on one box, does it need multiple firewalls, a DMZ, and an anal ex-banker with a big stick? In other words, do we chase after the grail of security architectures just because THEY tell us to?
Disclaimer: I love Scott Hanselman and am a big fan of his another layer of abstraction theory.