Recommendation engines transform human choice. Much as the steam engine energetically launched an industrial revolution, recommendation engines redefine insight and influence in an algorithmic age. Wherever choice matters, recommenders flourish. Better recommenders invariably mean better choices. Steam powers machines; recommenders empower people. They are the prime movers of their respective eras. They change how work gets done. That's why Amazon, Alibaba, Google, Netflix, and TikTok are more than mere engines of commerce; they're enablers of individual agency.

Their platforms provide instant insight and personalized options to every single user they serve. Their algorithms deliver data-driven suggestions explicitly designed to inspire immediate exploration. Their relentless relevance produces confident curiosity. These recommenders literally--numerically, quantitatively--predict what "people like you"--and you in particular--might want or need. That compelling value proposition has infiltrated digital interactions worldwide. The results speak for themselves: recommender systems influence the video people watch, the books they read, the music they hear, the videogames they play, the investments they make, the friends they meet, the clothes they wear, the food they eat, the restaurants they frequent, the wine they drink, the vacations they take, the news they monitor, the exercises they do, the companions they woo, the products they buy, the cars they drive or hail, the routes they travel, the software they code, the slides they present, the email they send, the classes they take, the art they collect, the babysitters and handymen they hire, the employees they promote, the photos they share, the academic research they review, the gifts they give, the live events they attend, the ads they see, the neighborhoods they live in, the jobs they apply for, the seeds they plant, the pharmaceuticals they take, and--cumulatively--how they actually and practically choose to live their lives. Wherever mobile devices connect--from Bangalore to Boston to Beijing to Berlin to Bogota--recommenders digitally nudge, advise, and invite more informed decision. Shopping, commerce, and consumption represent only the most obvious examples of their growing influence.