In the peak of the Internet bubble, a company's valuation-- and press attention-- would soar simply by whispering the words "John Doerr is an investor." But in early Web 2.0 days, the once-everywhere venture capitalist seemed to fall off of the tech press's radar, at least when it came to Internet investing. But boy, has Doerr made up for lost time this year: Keynoting both of our Disrupt conferences, holding press conferences at Facebook, and generally leading the charge on the messaging that Kleiner Perkins Caufield & Byers is serious about investing all over this mobile-social wave of digital innovation. The lastest move was his signing of Wall Street analyst Mary Meeker as a Kleiner Perkins partner-- a deal he personally negotiated with Meeker, according to an interview we did with both of them this morning. So I had to ask while I had him on the phone: Whatever happened to Doerr's belief that cleantech was the next big thing?