Two comments. Same subreddit. Same topic. Posted minutes apart. One has +847 karma. It sits at the top, gets gilded, spawns a thread of 200 replies. The person who wrote it gets DMs. Their next post gets upvoted reflexively because people remember the name. The other has +1. It exists somewhere below the fold, unseen by 99% of readers. Same words, different fate. That number — Reddit karma — is one of the most consequential invisible forces on the internet. It shapes what millions of people read, what opinions gain traction, whose voices carry weight in a community. And most Reddit users have a vague sense of how it works: upvotes good, downvotes bad, net score determines visibility. What almost nobody knows is what's actually happening inside Reddit's infrastructure every time someone clicks that arrow. The score you see? It's a lie. Not a malicious one. A mathematically necessary, deliberately constructed approximation — and the algorithm behind it is one of the most elegant ideas in distributed systems.…