Bullshit. The conclusions the author draws, that Gates was "anchored in the old paradigm of storage being a commodity that must be conserved" sounds like typical hand-wavy details-don't-matter business-person think. Microsoft is notorious for generating tons of internal e-mail. People go away on holidays and come back to 10K unread emails. More likely Bill knows how much e-mail he receives and roughly how much it grows per week/month. This guy tells him that he's burned through 1GB of e-mail in few months and that just doesn't add up to Bill. Either this reporter receives an order-of-magnitude more e-mails than Bill does or people have 1MB pictures in their signature blocks or something. So Bill starts drilling down and asking questions. Remember Bill is a fairly 'technical' guy (http://www.joelonsoftware.com/items/2006/06/16.html)

'He began firing questions. "How many messages are there?" he demanded. "Seriously, I'm trying to understand whether it's the number of messages or the size of messages." '

I don't interpret this to be gates questioning the necessity for more than 1GB of e-mail, just trying to get to the bottom of how this guy managed to use that much in a few months.