For me, it’s full text search.
I tend to want to find an opinion on something very specific, so if I can just toss a phrase or model number or name of something into a search field and get actual non-AI, non-advertisement, non-stupid-shit results, that’d be absolutely ideal.
Like, say, how Google worked 15 years ago.
The problem I ran into is that every single platform that primarily interacted with Mastodon (The keys, etc.) had the same exact same set of problems.
While yes, my Firefish instance had search, what was it searching? Local data only, and once I figured out that Mastodon-style replies didn’t federate to all of someone’s followers, it became pretty clear that it was uh, not very useful.
You can search, but any given server may or may not have access to data you actually want and thus, well, you just plain cannot meaningfully search for shit unless you go to one of the mega instances, or join giant piles of relays and store gigabyte upon gigabyte upon gigabyte of garbage data you do not care about.
The whole implementation is kinda garbage for search-based discovery from it’s very basic design all the way through to everyone’s implementations.