Seems not that expensive to crawl, index and firehose-ify pretty much all of Nostr in its current state. As far as I know Primal's doing it, Ditto's doing it, Nostr.band's doing it, and maybe Nostr.wine's doing it too. Who else?

That trends spreads it'll become a globally-indexed relay system with multiple global indexers.

I'm also not sure that's a bad thing. Or a good thing. Have to let it seep in.