[downer90]

To sum it up, after 20 paragraphs:

  So: the technical reason we started counting arrays at 
  zero is that in the mid-1960′s, you could shave a few 
  cycles off of a program’s compilation time on an IBM 7094. 
  The social reason is that we had to save every cycle we 
  could, because if the job didn’t finish fast it might not
  finish at all and you never know when you’re getting 
  bumped off the hardware because the President of IBM just 
  called and fuck your thesis, it’s yacht-racing time.

[roel_v]

Except that's not even what the guy who emailed it said. He said nothing about compile time - he said basically 'computers work with offsets, and the first element is at offset 0'. But that would have been against the preconceived notion of the author that there is something special about starting at 0, so he needed to make something up to make his 'article' fit.

(not harping on you, just stating for the TL/DR's looking for a summary)