Every start-up entrepreneur should tune-in to this fascinating debate between David Heinemeier Hansson and Jason Calacanis on TWiST. For those of you who haven't heard of him, Hansson is actually the Danish creator of Ruby on Rails and a founder of 37signals. He's a truly original thinker and makes a consistent and compelling case for the supremacy of profits (not revenue!) as the ostensible goal of a start-up.