Thirty-two thousand years ago, your many-times-great-grandparents Oog and Aag drew pictures on the wall of a cave. They had an innate need to communicate, but no written language. So they found an easy and natural way to share their thoughts and stories. Today, after so many years when speaking and writing dominated, we're back in another highly visual age. About 90 percent of everything shared online is now visual—selfies, GIFs, smartphone videos, and more. This explosion of communication through pictures isn't a millenial-driven fad; it's as natural as those lines first drawn by Oog and Aag. Just turbo-charged by the latest technology.