@Spiricom Search on Mastodon is (in my opinion) unusable because it only finds posts with hashtags and doesn't do full-text search.
That's a deliberate decision from the project leadership, they argue that it prevents harassment.
I disagree with that, I think it both inhibits discourse and makes useful posts disappear into the void, while malicious users can get at the data anyway (e.g. Google indexes some of Mastodon already). I'd say it does more harm than good.