Recently, I was working on site speed for a client with one page that makes a large number of custom database queries through WordPress’s WP_Query API.

A guy named Anh read our article on custom taxonomies and custom fields, and contacted us pointing to a similar article he wrote on his own site. His article’s good—what I like about it, specifically, are the bolded key points on the differences between taxonomies and fields, such as:

One of the most common needs for WordPress content is to add additional data to it beyond what already exists (category, author, content, etc.). If this data exists to organize posts, it’s “taxonomic” in nature and is best handled by custom taxonomies.