The holiday period is a quiet business time in Silicon Valley. Most people don't get the kind of time off we take as routine.

Instead, they work through the 24th and are back in the office on the 26th, not having St Stephen's Day to helpfully add a day for digestion to follow the day of gluttony. Then it's work again through the 31st and back in by the time the hangover is waning on the 2nd.

Still, on the technology business side, little happens from late December through to very early January. Executives can be hard to track down, if you are a journalist pursuing a story. Perhaps that's why we all traditionally opt for the year-end overview pieces that leave us reliant on research and our own knowledge of companies and the past year's business climate, rather than on reaching some senior vice-president.

But you can still gauge a lot of what is happening in the Valley during this period if you are a visitor by checking like a tracker for the tell-tale spoor left across the Santa Clara County landscape.

The most obvious indicator - and my personal favourite for judging the local economy - remains the "to let" sign, once an exceedingly rare species, but in the past few years, a distressingly common site. And such signs are not just hanging off the non-descript boxy offices in the Valley's bland industrial parks. They continue to be spotted on prime real estate in some of the Valley's most desirable locations.

On this visit, I found they continue to be found on Sand Hill Road, the winding boulevard of the venture capitalists in the oak-covered foothills adjacent to Stanford University. They are stuck in the expensive rolled turf lawns of so-called landmark Valley buildings, which are not, as you might suspect, famous old or valued architectural structures but the former flashy headquarters of now-downsized companies or bombed dotcoms.

One cold but sunny Valley day at December's end, my mother and I drove to visit a new landmark building, one that has created more excitement and controversy than most others in the past few years: the huge new IKEA store in East Palo Alto.

The arrival of IKEA to this end of the Bay Area brought the same sort of anticipation once reserved for especially propitious internet company initial public offerings. Now, the thought of bargain Scandinavian furniture and kitchenware items has residents twitching with excitement.

To get to IKEA, we drove past a quiet, tree-shaded clutch of industrial offices with "to let" signs outside. Weren't these same buildings available on my last visit during the summer, I ask? She confirms this is the case.

Their sad desertion signals that, despite predictions of rosier times ahead, the Valley is still hard-hit, more so than many other regions of the US. There's a peculiar kind of pain that comes from viewing such obvious signs of the Valley's distress. I grew up in this area, and love its energy and excitement and optimism. It's the American Opportunity boiled down to its invigorating essence. I love watching it all tick, and this rare downturn is a miserable thing indeed.

Nonetheless, for me, the fact that such buildings, even if only half-full, are in this area of townfuels my optimism for the region.

That technology and internet companies - and shoppers' mecca IKEA - are located in East Palo Alto at all is a testimony to the boom that preceded the bust. Though it bears the "Palo Alto" moniker - the most affluent city centre of the Valley's tech-driven neighbourhoods - nearby East Palo Alto was a stunted and dangerous place, literally across the railroad tracks,with a struggling, mostly ethnic minority population and one of the highest crime rates not just in California but the US.

East Palo Alto is slowly being transformed because its land and location is valuable. This makes it attractive to office developers and retailers like IKEA, who can reach a vast regional population by building on land that is underpriced compared to San Jose.

The challenge for East Palo Alto will be to take care that its growing attractiveness and prosperity benefits its existing population rather than forcing these people out. Local leaders have gone some way to ensure that this is so; for example, by requiring that IKEA hire a certain number of employees from local neighbourhoods.

Yet, the locals face the same daunting reality as many Irish people who find their once-modest homes have become pricy bijou residences for young employees grown rich from the boomtime tech economy. East Palo Alto, for so long the forgotten Valley city, always seemed to sit outside the golden river of cash that flowed from the tech sector. With good planning, such once-blighted places can nowbecome wholesome neighbourhoods again.