People like to play. So we invented games and placed them on boards. And then computers came. Now we can play against the computer or against human opponents all over the world – or right next to us.When we play against human opponents we want to have a ranking that will show others how good we are. Maybe it will scare opponents. Or we could just rub someone’s nose in our greatness. Or use our stats to feed our ego. And it would be nice if we could review previous games and learn from our mistakes.