Has Twitter learned anything from the Dot-com bust?

Evan Williams, the CEO of Twitter, hedges a bit when asked what is Twitter's revenue model in this video from the Web 2.0 Summit.  He does acknowledge that they are working on the product and the quality of the product will influence revenue. Ok. Start with a good product that people really want and build customers. This was a good step for Twitter and one that was not taken by many revenue-less dot-com companies. However, there still needs to be a revenue model. Most of the companies that provide free services have revenue: Gmail/Google Search, Facebook/Advertising, etc. Twitter cannot survive on VC money forever. I find it a bit disconcerting that the CEO, who is responsible for the strategic and conceptual aspects of the operation, cannot even articulate how they will make money. Are they working on partnerships (one was announced today with Bing) and cannot disclose it. Or do they truly believe that building a great product MUST somehow eventually lead to making money?