It's the grand irony of Wi-Fi, a remarkably useful way of connecting to the Internet which has nevertheless proved to be a tough business to make money in. Aruba Networks, a maker of Wi-Fi equipment, is rumored to have twice spurned Cisco's advances. Its shareholders will likely regret that; the company, which went public last year, has seen its shares plummet more than 90 percent from their peak. And it is now laying off 10 percent of its staff, we hear cutting costs by 10 percent, including some layoffs. Aruba's equipment was designed to withstand war-zone explosions — but not market implosions. Update: The company has reported earnings and confirmed costs cuts of 10 percent, though not all of that will come through the elimination of jobs.