An anonymous reader writes: Organized labor doesn't rack up a lot of wins these days, and Silicon Valley isn't most people's idea of a union hotbed. Nonetheless, in the past three years unions have organized 5,000 people who work on Valley campuses. Among others, they've unionized shuttle drivers at Apple, Tesla, Twitter, LinkedIn, EBay, Salesforce.com, Yahoo!, Cisco, and Facebook; security guards at Adobe, IBM, Cisco, and Facebook; and cafeteria workers at Cisco, Intel, and, earlier this summer, Facebook. The workers aren't technically employed by any of those companies. Like many businesses, Valley giants hire contractors that typically offer much less in the way of pay and benefits than the tech companies' direct employees get. Among other things, such arrangements help companies distance themselves from the way their cafeteria workers and security guards are treated, because somebody else is cutting the checks. Silicon Valley Rising, a coalition of unions and civil rights, community, and clergy groups heading the organizing campaign, says its successes have come largely from puncturing that veneer of plausible deniability. That means directing political pressure, media scrutiny, and protests toward the tech companies themselves. "Everybody knows that the contractors will do what the tech companies say, so we're focused on the big guys," says Ben Field, a co-founder of the coalition who heads the AFL-CIO's South Bay Labor Council. Labor leaders say their efforts have gotten some tech companies to cut ties with an anti-union contractor, intervene with others to ease unionization drives, and subsidize better pay for contract workers. "If you want to get people to buy your product, you don't want them to feel that buying your product is contributing to the evils of the world," says Silicon Valley Rising co-founder Derecka Mehrens, who directs Working Partnerships USA, a California nonprofit that advocates for workers. Tech companies have been image-conscious and closely watched of late, she says, and the coalition is "being opportunistic."