You know, I was all set to make gentle fun of this Business 2.0 piece on 2007: The (New) Year of the Tech IPO. It even comes with "six hot IPOs to watch," not to mention 20 fantasy-league investments as dream'd by various Valley VCs (Tim Draper! Elon Musk! Steve Case! Bill Gurley!). But then, the main article climaxes with, "There will be no irrational exuberance this time around." There it is! The first characteristic of this bubble that makes it different from the last one. Otherwise identical so far, but thank God our exuberance is now totally rational.