LAST MONTH, a Prussian-blue ballet slipper emoji made its debut on Apple’s new operating system. Florie Hutchinson, a 38-year-old publicist, appealed to Apple for a flat-shoe emoji last year after discovering that when she typed the “e” of “shoe” into her iPhone keyboard, a red stiletto automatically popped up. She realized that all three women’s shoe emojis featured heels, which didn’t reflect her reality. “I’ve spent the past five years in the Bay Area,” she said, “and if you go outside and count how many high heels you see it’s basically zero.”

The...