BOSTON--Economic bubbles are now famous, and the collapse of the dot-com business a decade ago made the bursting of bubbles infamous. A panel of experts here at the Going Green East conference yesterday ended up in a lively, entertaining and at times contentious debate over whether the growth of so-called clean tech--renewable energy and environmentally friendly technologies--has entered the bubble stage, if that bubble is bursting...or if a bubble has ever existed.

Lucky for anyone reading these words, the conference organizers at Always On videotaped the panel and have already posted it online for viewing (use this link then scroll two-thirds down the page to the embedded session title "The Cleantech Bubble?"). The first 10 minutes have some of the best fireworks from two pioneers of major technology ramp-ups, including Bob Metcalfe , who invented the Ethernet and drove the vast growth of the Internet, and George Gilder , whose prognostications about hot telecomm technologies and the darling companies behind them greatly pumped up the dot-com bubble. If you listen even longer you'll hear all four panelists ultimately bash subsidies for technology of all kinds, itself worth the price of admission--which in this case, is free.