Drew Houston said this quote

To the casual observer, the Dropbox demo video looked like a normal product demonstration, but we put in about a dozen Easter eggs that were tailored for the Digg audience. References to Tay Zonday and 'Chocolate Rain' and allusions to 'Office Space' and 'XKCD.' It was a tongue-in-cheek nod to that crowd, and it kicked off a chain reaction.