I agree with the basic idea that we want reputation, but the classic concept of reputation as a single number in the range (-inf, inf) is useless for solving real-world problems the way we solve them in the real world.
Why? Because my reputation in meatspace is precisely 0 with 99.9% of the world's population. They haven't heard of me, and they haven't heard of anyone who has heard of me. Meanwhile, my reputation with my selected set of friends and relatives is fairly high, and undoubtedly my reputation with some small set of people who are my enemies is fairly low. And this is all good, because no human being can operate in a world where everyone has an opinion about them all the time.
Global reputation is bad, and giving anyone a megaphone so they can chime into any conversation they want is bad, full stop. Megaphone-usage should not be a democratic thing where a simple majority either affirms or denies your ability to suddenly make everyone else listen to you. People have always been able to speak to their tribes/affinity groups/whatever you want to call them without speaking to the entire state/country/world, and if we want to build systems that will be resilient then we need to mimic that instead of pretending that reputation is a zero-sum global game.
Social reputation IRL also has transitive properties - vouching from other high-rep people, or group affiliations. Primitive forms of social-graph connectedness have been exposed in social networks but it doesn't seem like they've seen much investment in the past decade.
So there's 8 billion people in the world approximately. Therefore you're saying that you have reputation (either good or bad) with 8e9 x 0.001 of them. That is 8 million people? Wow, you maintain a very large reputation, actually. I hope it's not bad reputation!
But all jokes aside, you're exactly right. Reputation is only relevant in your closer circles. Having a global reputation score would just be another form of the Twitter blue check mark, but worse.
I want to hear from people that I don't know, the average Joe, not from Hollywood, Fox News persons, or politicians. And I want to hear from reputable people in my circles, but not so much that I'm just hearing from the echo chamber.
Social media is just a really big game that people are playing, where high scores are related to number of followers. So dumb.
Why? Because my reputation in meatspace is precisely 0 with 99.9% of the world's population. They haven't heard of me, and they haven't heard of anyone who has heard of me. Meanwhile, my reputation with my selected set of friends and relatives is fairly high, and undoubtedly my reputation with some small set of people who are my enemies is fairly low. And this is all good, because no human being can operate in a world where everyone has an opinion about them all the time.
Global reputation is bad, and giving anyone a megaphone so they can chime into any conversation they want is bad, full stop. Megaphone-usage should not be a democratic thing where a simple majority either affirms or denies your ability to suddenly make everyone else listen to you. People have always been able to speak to their tribes/affinity groups/whatever you want to call them without speaking to the entire state/country/world, and if we want to build systems that will be resilient then we need to mimic that instead of pretending that reputation is a zero-sum global game.