Categorizing websites with tags

Well, today I killed sub-categories and I replaced it with tags. There are a lot of general pros & cons of using folders vs tags vs both when organizing stuff. For the Wild Wild Web, with stuff being websites, it really makes sense to use tags:
- For a curator, working with tags is easier and more flexible. Moving websites in a tree of sub-categories is more involved.
- For a visitor, finding interesting websites with tags is simpler: you can combine them for advanced filtering and they have pretty colors. Moving into sub-categories to discover websites felt clunky.
- A website usually has a main topic (ex: a library of things) and maybe a few sub-topics. For example, Internet Archive is a library of texts, movies, software, etc. It doesn't need to be more complicated than that.
Technically, I could have kept both features, but it would have made my developer life harder. I'm really trying to keep it simple with this project, so... bye bye sub-categories!