Part of being a great CEO is being a cheerleader. You can't do that being hidden.

There are many different types of leadership, some of which Zuckerberg has. Making Facebook into the culture mainstay it is has been a huge accomplishment. I am sure a lot of this is due to him. But he needs to be an effective communicator both internally and externally in order to succeed. He can have awesome ideas that are technically groundbreaking, but he needs to make others believe.