Conde Nast's Portfolio has an interesting interview with Evan Williams, CEO of Twitter. According to Williams, Twitter has only 25 employees, and none of them are business people. Twitter is currently hiring, so that roster is likely to change. When asked when the site will begin to make money, Williams said sometime in 2009. He is considering more creative revenue streams beyond simple advertising.
Here is a link to the article: http://www.portfolio.com/executives/features/2009/02/11/Twitter-CEO-Evan-Williams-Q-and-A