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The Lines of Code That Changed Everything

Apollo 11, the JPEG, the first pop-up ad, and 33 other bits of software that have transformed our world.
Satoshi Nakomoto

Back in 2009, Facebook launched a world-changing piece of code—the “like” button. “Like” was the brainchild of several programmers and designers, including Leah Pearlman and Justin Rosenstein. They’d hypothesized that Facebook users were often too busy to leave comments on their friends’ posts—but if there were a simple button to push, boom: It would unlock a ton of uplifting affirmations. “Friends could validate each other with that much more frequency and ease,” as Pearlman later said.

It worked—maybe a little too well. By making “like” a frictionless gesture, by 2012 we’d mashed it more than 1 trillion times, and it really did unlock a flood of validation. But it had unsettling side effects, too. We’d post a photo, then sit there refreshing the page anxiously, waiting for the “likes” to increase. We’d wonder why someone else was getting more likes. So we began amping up the voltage in our daily online behavior: trying to be funnier, more caustic, more glamorous, more extreme.

Code shapes our lives. As the venture capitalist Marc Andreessen has written, “software is eating the world,” though at this point it’s probably more accurate to say software is digesting it.

Culturally, code exists in a nether zone. We can feel its gnostic effects on our everyday reality, but we rarely see it, and it’s quite inscrutable to non-initiates. (The folks in Silicon Valley like it that way; it helps them self-mythologize as wizards.) We construct top-10 lists for movies, games, TV—pieces of work that shape our souls. But we don’t sit around compiling lists of the world’s most consequential bits of code, even though they arguably inform the zeitgeist just as much.

So Slate decided to do precisely that. To shed light on the software that has tilted the world on its axis, the editors polled computer scientists, software developers, historians, policymakers, and journalists. They were asked to pick: Which pieces of code had a huge influence? Which ones warped our lives? About 75 responded with all sorts of ideas, and Slate has selected 36. It’s not a comprehensive list—it couldn’t be, given the massive welter of influential code that’s been written. (One fave of mine that didn’t make the cut: “Quicksort”! Or maybe Ada Lovelace’s Bernoulli algorithm.) Like all lists, it’s meant to provoke thought—to help us ponder anew how code undergirds our lives and how decisions made by programmers ripple into the future.