Overall, 2011's been a healthy year for tech, and it’s been particularly healthy in Silicon Valley, which pulls in 40 percent of the nation’s venture capital, has low relatively low unemployment, and isn’t feeling the pain of the real estate meltdown that has traumatized most of the country. Twelve years ago, the Valley was surging in a similar way, and then it all came tumbling down. So is this another bubble or not? Bloomberg BusinessWeek says:

In Silicon Valley, all the Sturm und Drang of 2011 seemed as relevant as the Cricket World Cup. High unemployment? Crippling debt? Not in Silicon Valley, where the fog burns off by noon and it’s an article of faith that talented, hard-working techies can change the world and reap unimaginable wealth in the process. “We live in a bubble, and I don’t mean a tech bubble or a valuation bubble. I mean a bubble as in our own little world,” says Google Chairman Eric Schmidt. “And what a world it is: Companies can’t hire people fast enough. Young people can work hard and make a fortune. Homes hold their value. Occupy Wall Street isn’t really something that comes up in daily discussion, because their issues are not our daily reality.”

The difference this time around is that hype has to be backed up with results, or the hypesters will be punished. The big tech IPOs this year—LinkedIn, Zynga, and Pandora Media, for example—have stayed well within the stratosphere, something that might not have happened circa 1998. This time around, and investors expect revenue, not just promises. Valley boosters say that no matter what, “The Valley’s overwhelming bias toward optimism remains one of its greatest assets.”

John Seely Brown, former director of the famed Xerox PARC R&D lab, believes we are undergoing what he calls a “Cambrian moment” of technology change that is making it exponentially easier to build companies, rent supercomputers, and get access to sophisticated scientific tools. With those tools at the disposal of entrepreneurs and researchers, he says, the future is blindingly bright. “So it’s stunning to see how cynical everybody else is,” he says. “They are looking at the world through a rearview mirror, trying to preserve the past as opposed to seizing the moment and moving forward with greater imagination.”