1. Recently, a close friend sent me an e-mail with the subject line “Things I’ve Noticed As I Get Older.” The ten numbered observations ranged from the mundane (politics is getting stupider) to the poignant (the distant melancholy of Facebook’s News Feed, with its dispatches from lives that were once, and now no longer, close to one’s own). But with all due respect to the observational chops of my correspondent, it wasn’t so much the content of the message that impressed me as its form. It was an e-mail in the shape of a listicle, a personal correspondence structured for the purposes of frictionless social-media sharing. At some level, it seemed, my friend intended his e-mail to go viral within the highly targeted demographic of me. I couldn’t help feeling that some basic epistolary protocol had been breached, that I was seeing an early sign of what could be a shift in the way people communicate. In the not too distant future, all human interactions, written or otherwise, might well be conducted in the form of lists—for ease of assimilation, for catchiness, for optimal snap. I imagined myself, some decades from now, nervously perched on the papered leatherette of an examination bed, and my doctor directing her sad, humane eyes at me a moment before clearing her throat and saying, “Top Five Signs You Probably Have Pancreatic Cancer.”