The one thing that is very interesting about Evan Williams is the ability to pull off TWO possible companies that were Google aquire capable. Blogger he already sold. Twitter he may.
Another way to look at it is, Twitter may have been already acquired by Google had not Evan Williams already had one company bought by Google. This may have stopped it from getting to the point it is now judging by some companies success after that event.
One major success is probably lucky, TWO is probably skill, or else a complete craziness by consumers. But what it is looking like is Evan Williams has created 2 successful companies in one bubble and coming out the end of the bubble it appears twitter might have some of the best value built in.