Hash IDs

Catalogs have a boring problem. Most items are nearly invisible. A platform may have millions of products, posts, videos, restaurants, songs, or ads, but user interaction is never evenly distributed. A small number of head items collect enough clicks, saves, purchases, and dwell time to become statistically legible. The rest live in the long tail, where the system is expected to recommend them intelligently despite barely having seen them. Very democratic. Very inconvenient. ...