A big number of broad categories and less broad subcategories down to narrow ones of low traffic should not be a problem, as long as people reading their titles can easily distinguish them. There will always be threads that are relevant to more than one categories, that’s not a problem either. The problem is when subcategories are relevant to more than one categories. I believe that’s the meaning of “specificity” @vchuravy suggests.
There are more than one ways to construct a tree of categories. In multi-word category names, the important word to construct a tree after is the first one. For example:
- “Scientific Computing” could house “Biology”.
- “Computational Science” could house “Computational Physics”.
- “Numerical Analysis/Methods” could house “Differential equations”.
Mixing competitive ways would confuse users, so it’s important the name choices to be consistent across the tree. Even if an individual name is not the most fashionable in the respective scientific community, people will still understand it when they read it. Therefore, instead of discussing individual category names in separate threads, we should use a wiki to discuss all names in parallel. Unlike with package names, where each team decided a name individually, the effort here in Discourse is to integrate the ecosystem, so as to make its value higher than the sum of its parts, for the benefit of the whole Julia community.