Search is almost certainly going to need something beyond the protocol to be of any use, and will most likely be best resolved at the individual application level.

Nostr is the scaffold you build on, it's universal verified unique user identity management, not the content.

I find the search function in the global feed on Amethyst does not seem to work. It'll find # and people I already follow, but nothing new. I have to search on desktop with Snort.