TED: Margaret Gould Stewart: How giant websites design for you (and a billion others, too) - Margaret Gould Stewart (2014)

Summary: 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.