Pagerank was great when it was new because it had never been used before. Once Google got popular enough to be worth gaming, it became an example of Goodhart's

Pagerank was great when it was new because it had never been used before. Once Google got popular enough to be worth gaming, it became an example of Goodhart's Law. https://en.wikipedia.org/wiki/Goodhart%27s_law https://en.wikipedia.org/wiki/Goodhart%27s_law