To me, the points are a way for other readers to signal agreement without needing to clutter the thread with dozens of "me too" comments. A score of 50 gives a

To me, the points are a way for other readers to signal agreement without needing to clutter the thread with dozens of "me too" comments. A score of 50 gives a comment the force of many voices, but it compacts those voices into two efficient bytes. Sure, it's a noisy signal because scores don't just indicate agreement, but the context usually makes that clear. If a factual claim is up- or downvoted, it usually indicates that people believe the claim is true or false. For analysis or opinion, it may have to more with whether the comment is insightful or thought-provoking.