Their search index was great back in the 90s simply because it was so localized to a specific interest, location, theme, etc. Wayfinding was a hell of a lot nicer back then, but didn't scale in the face of Google. I do miss the intimacy of search on Yahoo from back then.
And it was easy to control _how_ and _where_ you wanted your site to appear in the index. It's naive to think something similar would survive endless spam nowadays, but damn, I liked and really miss it.