The rise in the unemployment rate last month to 9.2 percent has Democrats and Republicans reliably falling back on their respective cure-alls. It is evidence for liberals that we need more stimulus and for conservatives that we need more tax cuts to increase demand. I am sure there is truth in both, but I do not believe they are the whole story. I think something else, something new — something that will require our kids not so much to find their next job as to invent their next job — is also influencing today’s job market more than people realize.

Look at the news these days from the most dynamic sector of the U.S. economy — Silicon Valley. Facebook is now valued near $100 billion, Twitter at $8 billion, Groupon at $30 billion, Zynga at $20 billion and LinkedIn at $8 billion. These are the fastest-growing Internet/social networking companies in the world, and here’s what’s scary: You could easily fit all their employees together into the 20,000 seats in Madison Square Garden, and still have room for grandma. They just don’t employ a lot of people, relative to their valuations, and while they’re all hiring today, they are largely looking for talented engineers.

Indeed, what is most striking when you talk to employers today is how many of them have used the pressure of the recession to become even more productive by deploying more automation technologies, software, outsourcing, robotics — anything they can use to make better products with reduced head count and health care and pension liabilities. That is not going to change. And while many of them are hiring, they are increasingly picky. They are all looking for the same kind of people — people who not only have the critical thinking skills to do the value-adding jobs that technology can’t, but also people who can invent, adapt and reinvent their jobs every day, in a market that changes faster than ever.

Today’s college grads need to be aware that the rising trend in Silicon Valley is to evaluate employees every quarter, not annually. Because the merger of globalization and the I.T. revolution means new products are being phased in and out so fast that companies cannot afford to wait until the end of the year to figure out whether a team leader is doing a good job.