Notable venture capitalist George Zachary just went on Bloomberg West—not exactly home turf for market skepticism—and said he thinks we're in a tech bubble, as evidenced by ballooning company valuations and acquisition prices. We're not going to argue.

Anthony Noto just came out of Wall Street retirement for one big score: he's going to lead the Goldman Sachs blitz behind Twitter's IPO, hoping to make it the biggest tech stock craze of our time. And Noto knows something about crazes: he helped hype some of the worst tech stocks from the last bubble.