I think there is only two options. 1) Have an index created by a centralized entity like google 2) Have the nodes in the network create the index The first o

I think there is only two options. 1) Have an index created by a centralized entity like google 2) Have the nodes in the network create the index The first option is the easiest but can be biased on who gets to be on the index and their position on the index. Option two is hard because we need a sort of mechanism to generate the index from the subjective view of the nodes in the network and sync this to everyone in the network. The core problem here is not really the indexing but the structure of the internet, domains/websites are relatively dumb they can not see the network topology, indexing is basically trying to create this topology.