Relevant Search WordPress Plugin
Relevant Search actually replaces the default WordPress search with relevant results. After testing a ton of plugins on the Tuts+ network without any luck I finally had to write one that worked. Go check for yourself, search any of the Tuts+ blogs and see this very same plugin in all it’s searching glory. The basic idea behind this plugin was to add a FULLTEXT index to the post_title & post_content and run a bit of REGEX on the search terms using that index. Then once daily the plugin will update the index with wp_schedule_event() to keep the search results from becoming corrupted or invalid. The plugin just works and does not add extra queries to your WordPress site. There’s nothing to configure, just activate, and you’re done.