It can be very simple to setup. Think single binary to run, or lambda to deploy (yes this is possible) with the URL back to it.

I imagine a binary, with a simple Admin UI allowing you to crawl some domains recursively would be enough to index your own website, and then have those results shared.

Where I could see this being really useful, is let someone who knows everything about pokemon provide the index for searching pokemon information. Then when they federate, provide a taxonomy saying "for queries that have these words, call me". Suddenly you have a very high value search source for pokemon.

Throw in some zero click info information boxes and you have added a lot of value.