Silicon Valley companies aren't using as much office space as they used to

New office buildings are continuing to be built in San Francisco and Silicon Valley, but companies aren't using as much space. This may be an issue that spills into the housing sector.   New office towers are still sprouting like mushrooms in some pockets of San Francisco and Silicon Valley. The biggest tech companies are still expanding their office footprint. The media are still full of stories of mega-salaries for tech workers. And yet, employment growth of the phenomenal...