How much content they've actually put in their tagging system is just as interesting as how the tagging system works.
But yeah, I've always been impressed by how detailed and specific their tags were. That's A LOT of work! The power of porn, I guess. And as an added bonus, those tags now power AIs able to generate custom hentai on demand!
If you want to find some images by tags, you better stick with more generic ones.