Twitter CEO: Build it and money will come

"We are spending our time trying to create the best technology and product for as many users as possible. That's where all our value is going to come from."

--Twitter CEO Evan Williams in "Twitter hits tweenhood" in the new issue of Fortune, on newsstands next week and Fortune.com today. Having attracted more than $150 million in venture capital (and 55 million unique visitors monthly), Twitter has outpaced Google (GOOG) in money-raising...with meaningless revenues to show for it. But for this feat and for quickly building the communications platform into a global phenomenon, Fortune puts Williams and co-founder Biz Stone at No. 5 on its just-released 40 Under 40 list.