As far as I know so far (and I know nuttin' ya hear me? Nuttin') there are private relays and paid relays and all that. As for a directory of relays that lists specific content and subjects - It's a nice idea. A good idea even. This proves that you are not dumb at all and I know not of such technology. Maybe it does exist. It might be that we solve the zero-point energy problem before that happens but, hey, who knows what the future holds (apart from cyborgs, interdimensional portals, quantum AGI etc).