"Binders full of women" struck such a chord with the Internet after Mitt Romney said it during last night's debate, because it's just a really weird thing to say. It conjures up the mental image of a man sifting through the pages of a homemade catalog of females, as though he's lady-shopping. It's kind of creepy, and maybe you couldn't put your finger on exactly why. But maybe it's because before this, "binders full of women" already had some association with creepiness, and like Romney, with Mormonism.
Known as the "joy book," it's a register that the FLDS prophet allegedly keeps of girls who are eligible for marriage, most of whom are underage, and it serves as a dating pool for fundamentalist Mormon men looking to add more wives to their homes. While the "joy books" have been discussed by members of the faith that had fled their compounds before being married off to older men without their consent, they were most famously featured on an episode of Big Love, in which they're depicted, quite literally, as binders full of young women.
Obviously, while Romney is Mormon, he's not part of the FLDS sect, and he didn't mean to imply that his own "binders full of women" was at all sexual. But religious affiliation aside, it still means that, kind of like those FLDS men, Romney has trouble meeting women. It's really unsettling to think that he felt like he hadn't come across any females—in all of his 65 years—that was qualified enough to appoint to his cabinet, that he would even need those binders.