I see a lot of attempts to do Related Posts using WordPress plugins. However, a lot of these plugins are attempting to automate the process by comparing content.

This is madness. It’s:

• Error prone
• Slow
• Unreliable

It’s also overlooking the glaringly obvious. Related posts are posts that are about the same or similar thing. We already have and use a mechanism for organising similar posts, they’re called taxonomies. Clearly 2 posts in the WordPress category are related to each other, if they’re both tagged with performance then the chances they’re related is even higher. Perhaps they’re part of a series? You should create a custom taxonomy called something like ‘post_series’ so you can tie collections of posts together.

So when you want to display related posts, don’t build an index or compare your posts content, title, or meta to every other posts content, title, or meta, just show random posts that are tagged with the same categories/tags. After all your content should be appropriately tagged and categorised, you may even have an automated post tagging system going on. You can even setup a related posts taxonomy to define exactly which post is related to which! But comparing content is for the Googles and Amazons of the internet.