Add a section about Meta queries, and scale, namely how they don't scale ( no INDEX on the meta table ), and how there are better ways of doing it for improved performance ( taxonomies ) and why it's usually not the right way to do it if you need to search for all posts with meta key X and value Y
Add a section about Meta queries, and scale, namely how they don't scale ( no INDEX on the meta table ), and how there are better ways of doing it for improved performance ( taxonomies ) and why it's usually not the right way to do it if you need to search for all posts with meta key X and value Y