My Google Summer of Code 2009 student, Justin Shreve, has done an excellent job creating a new search API for WordPress. We hope this API will be integrated into the WordPress core because it would simplify replacing the core search functionality and encourage developers to create many more options for searching blogs.
Justin’s Search plugin is actually a package of three plugins. The first plugin installs the API that lets other plugins do the searching. The other two plugins use the API to provide search systems that we think will please most users who are dissatisfied with the built-in WordPress search results: MySQL Fulltext and Google Custom Search. (The Google plugin requires a Google account.) For the search-savvy, Justin also wrote a Sphinx-based plugin, Sphinx Search. This last one involves installing additional software on the server.
I’m running the Fulltext plugin on my personal blog so you can try it. Enter a search in the sidebar. On the search results page you can refine your search by specifying whether to search posts, pages, and comments. You can also sort the results by relevance, date, or alphabet. The Advanced Search link leads to a form where you can specify author, categories, tags, and date range.
Self-hosted WordPress users can install Search. (It is not available for WordPress.com… yet.) After activating the main Search plugin you must also activate one of the other plugins: MySQL Fulltext, Google Custom Search, or Sphinx Search. We are anxious to know what you think of it. Justin plans to continue to improve the search system so he will need lots of user feedback.