He has said before that he dresses the way he does because he doesn't give a **** what anyone thinks about him.
I think it is very telling for Microsoft that they weren't represented there. You had Yahoo!, Cisco Systems, Twitter
Oracle, NetFlix, Apple, Genentech, Google, The Westly Group, and Facebook.
Its all about respect for the office. The others are wearing jackets and/or button-up shirts. Just because you don't give a ____ does not mean you have to be disrespectful and show your lack of class.