Why Approximation Works: Scaling Video Heatmaps with HyperLogLog

HyperLogLog allows video platforms to count distinct viewers with minimal storage by trading tiny accuracy losses (1.6% error) for massive efficiency gains. Instead of storing hundreds of millions of watch events per day, TopVideoHub's system uses fixed-size sketches that merge across regions and time buckets in milliseconds. This pattern—accepting reasonable approximation to enable real-time analytics—is increasingly essential for platforms operating at streaming scale.