Earlier quoted context omitted.
But a web of trust based on, "I like this reviwer, so I trust who they trust" seems reasonable.
I am really curious if this would actually work. I also think if you trust a reviewer and it turns out they are a bad reviewer than your trust rating should lower. (you turned out to be a bad reviewer reviewer) That said I have no idea if this would. Seems those 87k people mentioned above would just trust each other to raise their trust ratings.
It's more like Linkedin: if someone adds you and they are a mutual connection with a bunch of coworkers you like, that's good. But if their mutual connections are all social climbing spammers, you know they either are one themselves or don't know enough not to fall for that stuff.