How giant websites design for you (and a billion others, too)

Facebook’s “like” and “share” buttons are seen 22 billion times a day, making them some of the most-viewed design elements ever created. Margaret Gould Stewart, Facebook’s director of product design, outlines three rules for design at such a massive scale – one so big that the tiniest of tweaks can cause global outrage, but also so large that the subtlest of improvements can positively impact the lives of many.