3 A BRIEF HISTORY OF RECOMMENDATION ENGINES

From computationally crude and heuristically humble beginnings, recommendation engines rapidly evolved to define and dominate user experience online. The real-time recommendation and personalization that help make Alibaba, Amazon, Facebook, Netfix, YouTube, and Tencent so compelling have their origins in technical innovation and entrepreneurship pioneered in the 1990s. Less than a generation later, seemingly incremental research initiatives disruptively transformed behavioral norms and expectations worldwide. Recommenders make the digital world go round.