normal accidents (perrow 1999)

complexity, coupling, and catastrophic potential
inspired by accidents like TMI, chemical plant mishaps, aircraft collisions
also a postscript on Y2K written in 1999

compelling delineation of four classes of victims affected by an accident
(1) operators (2) users (3) system outsiders (4) future (fetus, future user) 

passive versus active risks
passive -- safety beyond user control
airline, concerts, shopping malls 
generally someone else making a profit. 
using Internet is passive risk for most people
but can be passive as in conscious but not intentional risk ('price of convenience')
but on the Internet many folks not even conscious of the risks they take
as if sysadmins need to be told this