Recommendations we get from websites about what to buy are often powered by an algorithm known as collaborative filtering. We trace this technology back to one person trying to declutter his inbox.

Recommendation systems first came to prominence through Amazon (NASDAQ:AMZN) suggesting what people might like based purchase history. That then expanded to more stores and to streaming services. Now ...

Ever since Amazon first deployed its recommendations system based on human curation and best-seller lists across its ecommerce platform two decades ago, product recommendations have been an important ...