Simple recommendation plugin for WordPress. Used as toy example for a talk about Machine Learning in WordPress
The plugin computes similarity between two texts via Jaccard/Tanimoto coefficient.
Similarities are stored in wp_postmeta for each post; as a result WP stores a similarity graph that can be queried quickly to output recommendations (which is, the most similar posts to the one currently in page).
Two hooks are used:
save_post: when a post is saved, it gets compared to the latest posts and results are saved (for each post) inwp_postmetaas an array.the_content: when a post is showed in page, the recommended posts are extracted from the array inwp_postmeta.