More than 18,000 creative projects got off the ground last year by the grace of Kickstarter, the crowdfunding site once known merely as a launchpad for starving artists. Kickstarter reports that its 2.2 million members pledged more than $319 million in 2012, up 221 percent from the year before. But more striking, perhaps, is the scale of some of Kickstarter’s latest success stories.