Priorities USA, a super PAC supporting Democratic front-runner Hillary Clinton, is gearing up for what it is touting as the largest digital ad buy of the 2016 presidential cycle. The group is reserving $35 million in online ad space targeting voters in Colorado, Florida, Iowa, Nevada, New Hampshire, Ohio and Virginia. The demographic focus will be on millennials, Hispanics, African Americans and women. With an eye on the general election, these ads will run during the summer.