I honestly don't understand how anyone could even begin to think such system is a good idea. We already have credit ratings, they are far less invasive than wha

I honestly don't understand how anyone could even begin to think such system is a good idea. We already have credit ratings, they are far less invasive than what you've described, they cover only one particular aspect of trust and they still suck. It will only get worse from there. The only rating system I've seen that mostly works is Ebay. The only reason it works is because it rates clear-cut transactions that are limited in time and scope, and where both parties have something to loose. And even there you have problems, like its notorious bias against sellers. Decentralized system would be even easier to game.